Fat to drop into liquid (5)
I believe the answer is:
plump
'fat' is the definition.
(I know that fat can be written as plump)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for plump that I've seen before include "Chubby, round" , "Rather fat" , "Full of figure" , "Not obese, just pleasantly rounded" , "Chubby, fat" .)