Victor with member, in truth, initially a pest (7)
I believe the answer is:
varmint
'a pest' is the definition.
(I've seen this before)
'victor with member in truth initially' is the wordplay.
'victor' becomes 'v' (phonetic alphabet: alpha, bravo, charlie etc.).
'with' is a charade indicator (letters next to each other).
'member' becomes 'arm' (arm is a kind of member**).
'initially' indicates taking the first letters.
The initial letter of 'truth' is 't'.
'v'+'arm'+'in'+'t'='VARMINT'
(Other definitions for varmint that I've seen before include "Troublesome wild animal, especially a fox (US)" , "Mischievous person" , "pest" , "rascal" .)