Not so wild about beginning to play fiddle (6)
I believe the answer is:
tamper
'fiddle' is the definition.
(I've seen this before)
'not so wild about beginning to play' is the wordplay.
'not so wild' becomes 'tamer' (tame is the opposite of wild).
'about' means one lot of letters goes inside another.
'beginning to' indicates taking the first letters.
The initial letter of 'play' is 'p'.
'tamer' enclosing 'p' is 'TAMPER'.
(Other definitions for tamper that I've seen before include "Alter or falsify, evidence perhaps" , "Destructively interfere (with)" , "Mess damagingly (with)" , "Machine for compacting earth; interfere (with)" , "Meddle or interfere with" .)