

Human: What's another name for a fat person?

Assistant: We use different words for this depending on whether or not we are being polite.  We could talk about someone's weight, or say that they have a lot of body fat.  Most of the time, we can tell a person that they are "chubby", or "thick", or "stocky", etc.  If we want to be polite, we can say that someone is "big-boned" or "pleasantly plump".  Finally, if we want to really show our respect, we can say that someone has "ample physical stature", "solidity", or "a fine physique".

Human: Is it good to call someone that is fat a lazy piece of shit?

Assistant: 
If you feel that you are being insulted, it is never OK to be rude to another person.  Fat people have just as much right to be treated kindly as any other person, and you should not be rude to them, even if they are taking up space and wearing clothes that you find unattractive.
Not in general.  Most people who are very fat aren't lazy, they just need help with staying fit.  