Belligerent wife even maintaining resistance (7)
I believe the answer is:
warlike
'belligerent' is the definition.
(I've seen this before)
'wife even maintaining resistance' is the wordplay.
'wife' becomes 'w' (abbreviation).
'even' becomes 'alike' (both can mean similar or the same).
'maintaining' means one lot of letters goes inside another (inserted letters are held or maintained).
'resistance' becomes 'r' (electronics abbreviation).
'alike' going around 'r' is 'arlike'.
'w'+'arlike'='WARLIKE'
(Other definitions for warlike that I've seen before include "Martial" , "Bellicose" , "Hostile, belligerent" , "Militarily hostile" , "Military" .)