Cloudburst makes Roman stir uneasily (9)
I believe the answer is:
rainstorm
'cloudburst' is the definition.
(thesaurus)
'roman stir uneasily' is the wordplay.
'uneasily' indicates anagramming the letters.
'roman'+'stir'='romanstir'
'romanstir' is an anagram of 'RAINSTORM'.
'makes' acts as a link.
(Other definitions for rainstorm that I've seen before include "Heavy fall" , "Meteorological phenomenon" , "Heavy downpour" , "ferocious weather" , "Wild weather" .)