Wild fellow that is about to take cocaine (6)
I believe the answer is:
fierce
'wild' is the definition.
('fierce' can be similar in meaning to 'wild')
'fellow that is about to take cocaine' is the wordplay.
'fellow' becomes 'f' (abbreviation - of a society etc.).
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'about' becomes 're' (regarding**).
'to take' means one lot of letters goes inside another.
'cocaine' becomes 'c' ('C' can be a synonym of 'cocaine').
're' enclosing 'c' is 'rce'.
'f'+'ie'+'rce'='FIERCE'
(Other definitions for fierce that I've seen before include "Unpleasantly extreme, not gentle" , "Savage - vehement" , "Menacingly wild" , "Aggressive; intense" , "Barbarous" .)