Wild animal old boy caught in club (6)
I believe the answer is:
bobcat
'wild animal' is the definition.
(I've seen this before)
'old boy caught in club' is the wordplay.
'old boy' becomes 'OB' (abbreviation for a private school 'old boy').
'caught' becomes 'c' (cricket abbreviation).
'in' is an insertion indicator.
'club' becomes 'bat' (as in sporting equipment).
'ob'+'c'='obc'
'obc' placed into 'bat' is 'BOBCAT'.
(Other definitions for bobcat that I've seen before include "Type of lynx" , "North American lynx" , "Small lynx of Norht America" , "A sort of lynx" , "Wild animal" .)