Object of night out ... (5)
I believe the answer is:
thing
'object' is the definition.
(an object is a thing or item)
'night out?' is the wordplay.
'out?' indicates an anagram (I've seen 'out of' mean this).
'night' anagrammed gives 'THING'.
'of' is the link.
(Other definitions for thing that I've seen before include "Inanimate object" , "Object; gadget" , "Object, artefact" , "A creature" , "An unnamed object or item" .)