Puce rooms generate calmness (9)
I believe the answer is:
composure
'calmness' is the definition.
(synonyms)
'puce rooms generate' is the wordplay.
'generate' indicates an anagram.
'puce'+'rooms'='pucerooms'
'pucerooms' anagrammed gives 'COMPOSURE'.
(Other definitions for composure that I've seen before include "State of calmness" , "tranquillity" , "Aplomb" , "Calm state" , "Coolness" .)