Caustic Tim Vine? (7)
I believe the answer is:
pungent
'caustic' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
(Other definitions for pungent that I've seen before include "Incisive" , "bitter" , "Witty" , "Penetrating" , "Acrid; sarcastic (humour)" .)