Devise cabaret, if upset (9)
I believe the answer is:
fabricate
'devise' is the definition.
(thesaurus)
'cabaret if upset' is the wordplay.
'upset' indicates an anagram.
'cabaret'+'if'='cabaretif'
'cabaretif' with letters rearranged gives 'FABRICATE'.
(Other definitions for fabricate that I've seen before include "Tell lies" , "Invent, make up" , "forge" , "Construct or invent" , "Make up; manufacture" .)