Recruit for combat? (6)
I believe the answer is:
engage
I believe this clue is a double definition.
'recruit' is the first definition.
(thesaurus)
'combat?' is the second definition.
(thesaurus)
'for' is the link.
(Other definitions for engage that I've seen before include "Hire; get to grips with" , "Employ or take on" , "Thief (rhyming slang)" , "Pay to serve" , "Occupy (interest)" .)