Contemptible male American gets around in love (7)
I believe the answer is:
heinous
'contemptible' is the definition.
(thesaurus)
'male american gets around in love' is the wordplay.
'male' becomes 'he' (he refers to a man).
'american' becomes 'us' (abbreviation for United States).
'gets around' means one lot of letters goes inside another.
'love' becomes 'o' (love means zero in tennis).
'he'+'us'='heus'
'in'+'o'='ino'
'heus' placed around 'ino' is 'HEINOUS'.
(Other definitions for heinous that I've seen before include "Iniquitous" , "Shockingly wicked" , "Hateful" , "Very wicked, maybe in-house" , "Extremely evil" .)