Tickle bird, poorly fed (9)
I believe the answer is:
titillate
'tickle' is the definition.
('titillate' can be a synonym of 'tickle')
'bird poorly fed' is the wordplay.
'bird' becomes 'tit' (I've seen this before**).
'poorly' becomes 'ill' ('ill' can be a synonym of 'poorly').
'fed' becomes 'ate' ('eat' can be a synonym of 'feed').
'tit'+'ill'+'ate'='TITILLATE'
(Other definitions for titillate that I've seen before include "Excite erotically" , "create superficial interest" , "Interest superficially" , "arouse interest" , "Excite through suggestive means" .)