In conflict with lover, suspicious to some extent (6)
I believe the answer is:
versus
'in conflict with' is the definition.
(thesaurus)
'lover suspicious to some extent' is the wordplay.
'to some extent' says the answer is hidden in the clue.
'VERSUS' is hidden in the letters of 'lover suspicious'.
(Other definitions for versus that I've seen before include "Opposed to" , "Preposition meaning against, as in contest" , "playing" , "taking part in team sports" , "Against in games" .)