Inconsistent United Nations' record (8)
I believe the answer is:
unstable
'inconsistent' is the definition.
(thesaurus)
'united nations' record' is the wordplay.
'united nations'' becomes 'uns' ('UN' can be a synonym of 'united nations').
'record' becomes 'table' (I've seen this before).
'uns'+'table'='UNSTABLE'
(Other definitions for unstable that I've seen before include "insecure" , "Precarious or subject to change" , "Subject to change, variable" , "Shaky" , "Likely to collapse" .)