Sinônimos de "thin" (gaunt, slender, skinny)

Hello guys,

I have a question about the different meanings of the words gaunt, bony, thin, slender, skinny, slim, lean, I looked at the dictionaries and they give me all this words as synonyms, but I know they have differences when in usage, some are more negatives, others more positive, and others depend on the situation. Could you clarify me? And other thing I noticed is that in all their definitions of dictionaries, the word "thin" is given as the synonyms for all of them.

Thanks in advance for your answers and sorry for the number of words!