One starting booze, drinking booze before noon (8)
I believe the answer is:
beginner
'one starting' is the definition.
(I've seen this before)
'booze drinking booze before noon' is the wordplay.
'booze' becomes 'beer'.
'drinking' indicates putting letters inside (inserted letters are consumed or drunk).
'booze' becomes 'gin' (gin is a kind of booze).
'before' means one lot of letters go next to another.
'noon' becomes 'n'.
'gin'+'n'='ginn'
'beer' enclosing 'ginn' is 'BEGINNER'.
(Other definitions for beginner that I've seen before include "inexperienced person" , "Tiro, novice" , "Fresher" , "Starter" , "Tyro, rookie" .)