Enrage trendy partner (7)
I believe the answer is:
inflame
'enrage' is the definition.
(thesaurus)
'trendy partner' is the wordplay.
'trendy' becomes 'in'.
'partner' becomes 'flame' (flame can mean a romantic partner).
'in'+'flame'='INFLAME'
(Other definitions for inflame that I've seen before include "Bother" , "Excite passionate feelings" , "Exacerbate" , "Make (a situation) worse" , "Provoke; aggravate" .)