Very drunk on fewer (7)
I believe the answer is:
legless
'very drunk' is the definition.
(I've seen this before)
'on fewer' is the wordplay.
'on' becomes 'leg' (cricket term, fielding positions).
'fewer' becomes 'less' (associated in meaning).
'leg'+'less'='LEGLESS'
(Other definitions for legless that I've seen before include "Like snakes; drunk" , "Showing result of drinking" , "like a fish?" , "Slangily drunk, lacking lower limbs" , "very merry!" .)