Partner, hot on American group (7)
I believe the answer is:
husband
'partner' is the definition.
(I've seen this before)
'hot on american group' is the wordplay.
'hot' becomes 'h'.
'on' is a charade indicator (letters next to each other).
'american' becomes 'us'.
'group' becomes 'band' (band is a kind of group).
'h'+'us'+'band'='HUSBAND'
(Other definitions for husband that I've seen before include "Mate" , "Partner in marriage" , "Make careful use of" , "Farm" , "Economically manage" .)