Short fat girl (3)
I believe the answer is:
sue
'girl' is the definition.
(girl's name)
'short fat' is the wordplay.
'short' means to remove the last letter.
'fat' becomes 'suet' (suet is a kind of fat).
'suet' with its final letter taken off is 'SUE'.
(Other definitions for sue that I've seen before include "take to 10 [COURT] !" , "Take legal case against" , "Take court action" , "Make a legal claim" , "Start proceedings against (someone)" .)