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