Telling beer makes aggressive (11)
I believe the answer is:
belligerent
'aggressive' is the definition.
(I know that aggressive can be written as belligerent)
'telling beer makes' is the wordplay.
'makes' indicates anagramming the letters.
'telling'+'beer'='tellingbeer'
'tellingbeer' anagrammed gives 'BELLIGERENT'.
(Other definitions for belligerent that I've seen before include "Hostile, aggressive" , "hawk" , "fighting" , "Warlike" , "Aggressive - it'll be green (anag)" .)