ثوخ1 ثَاخَ and سَاخَ both signify He, or it, sank into the ground; and Yaakoob asserts that the ث in the former is a substitute for the س in the latter. (L, TA.) You say, ثَاخَتْ قَدَمُهُ بِالوَحْلِ, (S,) or فِى الوَحْلِ, (L,) aor. ـُ and تَثِيخُ, His foot sank, or entered, into the mire. (S, L.) and ثَاخَتِ الإِصْبَعُ, aor.  as above, (L, K,) inf. n. ثَوْخٌ, (L,) The finger entered, or sank, into a swollen, or tumid, or a soft, or yielding, substance; (L, K;) as also سَاخَت, (L,) and تَاخَت: (Lth:) but this last is disapproved by IDrd, and J and others do not mention it. (TA in art. توخ.)