Decline terms of free boob job (3)
I believe the answer is:
ebb
'decline' is the definition.
(I know that ebb is a type of decline)
'terms of free boob job' is the wordplay.
'terms of' indicates one should take the final letters (term can mean the end of something).
The last letters of 'free boob job' are 'EBB'.
(Other definitions for ebb that I've seen before include "Initially Mrs Browning's" , "Tidal retreat" , "Type of tide" , "(Sea) recede" , "Abate" .)