Object to night manoeuvres (5)
I believe the answer is:
thing
'object' is the definition.
(an object is a thing or item)
'night manoeuvres' is the wordplay.
'manoeuvres' indicates anagramming the letters (letters manoeuvred in a new way).
'night' is an anagram of 'THING'.
'to' acts as a link.
(Other definitions for thing that I've seen before include "Night (anag)" , "See 1" , "Body" , "Object; gadget" , "A creature" .)