Excellent, fast to accept male's complaint (7)
I believe the answer is:
ailment
'complaint' is the definition.
('ailment' can be a synonym of 'complaint')
'excellent fast to accept male's' is the wordplay.
'excellent' becomes 'ai'.
'fast' becomes 'lent' (I've seen this before).
'to accept' is an insertion indicator.
'male' becomes 'm' (common abbreviation).
'lent' enclosing 'm' is 'lment'.
'ai'+'lment'='AILMENT'
(Other definitions for ailment that I've seen before include "problem" , "Slight but persistent illness" , "Minor illness" , "Tummy upset, for instance" , "Tim Alen has an odd indisposition." .)