Nobbled animal about to finish last (3,2)
I believe the answer is:
got at
'nobbled' is the definition.
(I've seen this before)
'animal about to finish last' is the wordplay.
'animal' becomes 'goat' (I've seen this before).
'about' is an insertion indicator.
'to finish' indicates one should take the final letters.
The final letter of 'last' is 't'.
'goat' placed around 't' is 'GOT AT'.
(Other definitions for got at that I've seen before include "Unfairly influenced" , "Nobbled" , "Attacked verbally" , "Criticised" .)