Occasionally rein in disgusting male (6)
I believe the answer is:
virile
'male' is the definition.
('virile' can be a synonym of 'male')
'occasionally rein in disgusting' is the wordplay.
'occasionally' indicates alternate letters.
'in' indicates putting letters inside.
'disgusting' becomes 'vile' (I've seen this before).
The alternate letters of 'rein' are 'ri'.
'ri' put within 'vile' is 'VIRILE'.
(Other definitions for virile that I've seen before include "Potent" , "Having energy" , "Masculine and macho" , "male" , "Vigorous, manly" .)