Liberal Mike quietly consumed by booze (5)
I believe the answer is:
ample
'liberal' is the definition.
(I've seen this before)
'mike quietly consumed by booze' is the wordplay.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'quietly' becomes 'p' (p for piano and quiet).
'consumed by' means one lot of letters goes inside another.
'booze' becomes 'ale' (type of alcohol).
'm'+'p'='mp'
'mp' placed within 'ale' is 'AMPLE'.
(Other definitions for ample that I've seen before include "Plentiful; capacious" , "Fairly large" , "No more, please!" , "Sealed glass container for dose of medicine" , "Easily sufficient" .)