user471: In this question, we found the metaphorical use of the term "the world", different from its ordinary everyday meaning.
Similarly, the sutta SN 35.151 below talks about living the holy life without students and teachers, as well as living the holy life with students and teachers. A deeper look into the elaboration by the Buddha seems to indicate that "has students" and "has teacher" are metaphors.
What do these metaphors mean?
And what is the difference between "has students" and "has teacher" in this case? Why are they differentiated into two different things?

“Bhikkhus, this holy life is lived without students and without a
teacher. A bhikkhu who has students and a teacher dwells in suffering,
not in comfort. A bhikkhu who has no students and no teacher dwells
happily, in comfort.
“And how, bhikkhus, does a bhikkhu who has students and a teacher
dwell in suffering, not in comfort? Here, bhikkhus, when a bhikkhu has
seen a form with the eye, there arise in him evil unwholesome states,
memories and intentions connected with the fetters. They dwell within
him. Since those evil unwholesome states dwell within him, he is
called ‘one who has students.’ They assail him. Since evil unwholesome
states assail him, he is called ‘one who has a teacher.’
“Further, when a bhikkhu has heard a sound with the ear … cognized a
mental phenomenon with the mind … he is called ‘one who has a
teacher.’
“It is in this way that a bhikkhu who has students and a teacher
dwells in suffering, not in comfort.
“And how, bhikkhus, does a bhikkhu who has no students and no teacher
dwell happily, in comfort? Here, bhikkhus, when a bhikkhu has seen a
form with the eye, there do not arise in him evil unwholesome states,
memories and intentions connected with the fetters. They do not dwell
within him. Since those evil unwholesome states do not dwell within
him, he is called ‘one who has no students.’ They do not assail him.
Since evil unwholesome states do not assail him, he is called ‘one who
has no teacher.’
“Further, when a bhikkhu has heard a sound with the ear … cognized a
mental phenomenon with the mind … he is called ‘one who has no
teacher.’
“It is in this way, bhikkhus, that a bhikkhu who has no students and
no teacher dwells happily, in comfort.
SN 35.151


user254: Apparently for Pali word for having a teacher there is sācariyaka:


together with one’s teacher


... and for not having a teacher it is anācariyaka for which the dictionary gives two definitions:


not having a teacher; not dependent on an instructor
free from bad influences


"cariyaka" isn't defined in the PTS dictionary.
There's cariya which seems to mean "conduct" or "state of life"

Cariya Cariya (nt.) & cariyā (f.) [from car, carati] (mostly -˚) conduct, behaviour, state of, life of. Three cariyās at Ps i.79; six at Vism 101; eight at Ps ii.19 sq., 225 & four sets of eight in detail at Nd2 237b. Very freq. in dhamma˚ & brahma˚, a good walk of life, proper conduct, chastity — eka˚ living alone Sn 820; unchā˚ begging J ii.272; iii.37; bhikkhā˚ a life of begging Sn 700; nagga˚ nakedness Dh 141.

... plus the suffix "-aka":

-aka: is said to denote the property of: manussa, a man+a=manussakaṃ, that which belongs to man, the property of man, human (see -ka).
It also forms a numerous class of action-nouns and adjectives: √kar, to make, do+aka=karaka, making, causing or maker, doer; √gah, to take, receive+aha=gahaka, taking, receiving, a receiver: sometimes a -y is inserted between aka and a root ending in a vowel, especially long ā: √dā, to give +aka=dāyaka, a giver.

So "cariyaka" might mean literally something like "maker or causer of behaviour" -- which may be good or bad behaviour; and, more importantly, the "causer" might be a person (i.e. a teacher) or something more impersonal (e.g. a good or a bad habit).
So perhaps it isn't a "metaphor", but the English language (not always being steeped in anatta) might tend to imply strong distinctions between people and impersonal causes -- a distinction which doesn't clearly exist in Pali.

The word for resident student is santevāsika:


with resident pupils, i.e. with internal impurities


There's a non-canonical explanation here, The Disciple Within, by Bhikkhu Revata:

So, we have to find out exactly what our Buddha meant by the 'disciple within' and the 'master
within'. We have to find out and to see what sort of lives we are living in. It is time for us to re-examine
how we are living and what sort of mind-set we have. As tonight happens to be the eve of the New
Year 2008, I feel that this is a most appropriate time to reflect deeply upon this matter. That is why I
wanted to deliver this talk tonight.
Now, in every living being's mind there are the defilements of greed (lobha), the defilements of
hatred (dosa), and the defilements of ignorance (moha). Also, we have within us envy, stinginess
(issamicchaya) and conceit (màna). Each one of us, we all have these defilements. Whenever we see
something that we think is very desirable or undesirable, there arise in us evil unwholesome states that
bind us up like fetters. Our senses, our memories, our perceptions and our feelings become very busy
and active in arousing the unwholesome defilements (akusala). These defilements dwell within us.
Since they dwell within us, they are called the `disciples within.'

By analogy with the previous answer -- that "teacher" should be understood as "cause" -- I presume that "disciple" should be understood as an "effect" or "result".

471: <p>In <a href="https://buddhism.stackexchange.com/q/45355/471">this question</a>, we found the metaphorical use of the term &quot;the world&quot;, different from its ordinary everyday meaning.</p>
<p>Similarly, the sutta <a href="https://suttacentral.net/sn35.151/en/bodhi" rel="nofollow noreferrer">SN 35.151</a> below talks about living the holy life without students and teachers, as well as living the holy life with students and teachers. A deeper look into the elaboration by the Buddha seems to indicate that &quot;has students&quot; and &quot;has teacher&quot; are metaphors.</p>
<p>What do these metaphors mean?</p>
<p>And what is the difference between &quot;has students&quot; and &quot;has teacher&quot; in this case? Why are they differentiated into two different things?</p>
<blockquote>
<p>“Bhikkhus, this holy life is lived without students and without a
teacher. A bhikkhu who has students and a teacher dwells in suffering,
not in comfort. A bhikkhu who has no students and no teacher dwells
happily, in comfort.</p>
<p>“And how, bhikkhus, does a bhikkhu who has students and a teacher
dwell in suffering, not in comfort? Here, bhikkhus, when a bhikkhu has
seen a form with the eye, there arise in him evil unwholesome states,
memories and intentions connected with the fetters. They dwell within
him. Since those evil unwholesome states dwell within him, he is
called ‘one who has students.’ They assail him. Since evil unwholesome
states assail him, he is called ‘one who has a teacher.’</p>
<p>“Further, when a bhikkhu has heard a sound with the ear … cognized a
mental phenomenon with the mind … he is called ‘one who has a
teacher.’</p>
<p>“It is in this way that a bhikkhu who has students and a teacher
dwells in suffering, not in comfort.</p>
<p>“And how, bhikkhus, does a bhikkhu who has no students and no teacher
dwell happily, in comfort? Here, bhikkhus, when a bhikkhu has seen a
form with the eye, there do not arise in him evil unwholesome states,
memories and intentions connected with the fetters. They do not dwell
within him. Since those evil unwholesome states do not dwell within
him, he is called ‘one who has no students.’ They do not assail him.
Since evil unwholesome states do not assail him, he is called ‘one who
has no teacher.’</p>
<p>“Further, when a bhikkhu has heard a sound with the ear … cognized a
mental phenomenon with the mind … he is called ‘one who has no
teacher.’</p>
<p>“It is in this way, bhikkhus, that a bhikkhu who has no students and
no teacher dwells happily, in comfort.<br />
<a href="https://suttacentral.net/sn35.151/en/bodhi" rel="nofollow noreferrer">SN 35.151</a></p>
</blockquote>
 254: <p>Apparently for Pali word for having a teacher there is <a href="https://suttacentral.net/define/s%C4%81cariyaka" rel="nofollow noreferrer">sācariyaka</a>:</p>
<blockquote>
<ol>
<li>together with one’s teacher</li>
</ol>
</blockquote>
<p>... and for not having a teacher it is <a href="https://suttacentral.net/define/an%C4%81cariyaka" rel="nofollow noreferrer">anācariyaka</a> for which the dictionary gives two definitions:</p>
<blockquote>
<ol>
<li>not having a teacher; not dependent on an instructor</li>
<li>free from bad influences</li>
</ol>
</blockquote>
<p>&quot;cariyaka&quot; isn't defined in the PTS dictionary.
There's <a href="https://dsal.uchicago.edu/cgi-bin/app/pali_query.py?qs=cariya&amp;searchhws=yes" rel="nofollow noreferrer">cariya</a> which seems to mean &quot;conduct&quot; or &quot;state of life&quot;</p>
<blockquote>
<p>Cariya Cariya (nt.) &amp; cariyā (f.) [from car, carati] (mostly -˚) conduct, behaviour, state of, life of. Three cariyās at Ps i.79; six at Vism 101; eight at Ps ii.19 sq., 225 &amp; four sets of eight in detail at Nd2 237b. Very freq. in dhamma˚ &amp; brahma˚, a good walk of life, proper conduct, chastity — eka˚ living alone Sn 820; unchā˚ begging J ii.272; iii.37; bhikkhā˚ a life of begging Sn 700; nagga˚ nakedness Dh 141.</p>
</blockquote>
<p>... plus the suffix &quot;<a href="https://www.buddha-vacana.org/toolbox/suf.html#aka" rel="nofollow noreferrer">-aka</a>&quot;:</p>
<blockquote>
<p>-aka: is said to denote the property of: manussa, a man+a=manussakaṃ, that which belongs to man, the property of man, human (see -ka).</p>
<p>It also forms a numerous class of action-nouns and adjectives: √kar, to make, do+aka=karaka, making, causing or maker, doer; √gah, to take, receive+aha=gahaka, taking, receiving, a receiver: sometimes a -y is inserted between aka and a root ending in a vowel, especially long ā: √dā, to give +aka=dāyaka, a giver.</p>
</blockquote>
<p>So &quot;cariyaka&quot; might mean literally something like &quot;maker or causer of behaviour&quot; -- which may be good or bad behaviour; and, more importantly, the &quot;causer&quot; might be a person (i.e. a teacher) or something more impersonal (e.g. a good or a bad habit).</p>
<p>So perhaps it isn't a &quot;metaphor&quot;, but the English language (not always being steeped in anatta) might tend to imply strong distinctions between people and impersonal causes -- a distinction which doesn't clearly exist in Pali.</p>
<hr />
<p>The word for resident student is <a href="https://suttacentral.net/define/santev%C4%81sika" rel="nofollow noreferrer">santevāsika</a>:</p>
<blockquote>
<ol>
<li>with resident pupils, i.e. with internal impurities</li>
</ol>
</blockquote>
<p>There's a non-canonical explanation here, <a href="https://www.dhammatalks.net/Books8/Bhikkhu_Revata-The_Disciple_Within.pdf" rel="nofollow noreferrer">The Disciple Within</a>, by Bhikkhu Revata:</p>
<blockquote>
<p>So, we have to find out exactly what our Buddha meant by the 'disciple within' and the 'master
within'. We have to find out and to see what sort of lives we are living in. It is time for us to re-examine
how we are living and what sort of mind-set we have. As tonight happens to be the eve of the New
Year 2008, I feel that this is a most appropriate time to reflect deeply upon this matter. That is why I
wanted to deliver this talk tonight.</p>
<p>Now, in every living being's mind there are the defilements of greed (lobha), the defilements of
hatred (dosa), and the defilements of ignorance (moha). Also, we have within us envy, stinginess
(issamicchaya) and conceit (màna). Each one of us, we all have these defilements. Whenever we see
something that we think is very desirable or undesirable, there arise in us evil unwholesome states that
bind us up like fetters. Our senses, our memories, our perceptions and our feelings become very busy
and active in arousing the unwholesome defilements (akusala). These defilements dwell within us.
Since they dwell within us, they are called the `disciples within.'</p>
</blockquote>
<p>By analogy with the previous answer -- that &quot;teacher&quot; should be understood as &quot;cause&quot; -- I presume that &quot;disciple&quot; should be understood as an &quot;effect&quot; or &quot;result&quot;.</p>
