Rogue may bless parliament (8)
I believe the answer is:
assembly
'parliament' is the definition.
(thesaurus)
'rogue may bless' is the wordplay.
'rogue' indicates anagramming the letters (letters go rogue).
'may'+'bless'='maybless'
'maybless' anagrammed gives 'ASSEMBLY'.
(Other definitions for assembly that I've seen before include "Group meeting" , "School morning gathering" , "A gathering for formal meeting" , "Gathering for a special purpose" , "court" .)