Quietly turned dour and conceited (5)
I believe the answer is:
proud
'conceited' is the definition.
(similar in meaning)
'quietly turned dour' is the wordplay.
'quietly' becomes 'p' (p for piano and quiet).
'turned' indicates anagramming the letters.
'dour' is an anagram of 'roud'.
'p'+'roud'='PROUD'
'and' is the link.
(Other definitions for proud that I've seen before include "Guilty of deadly sin" , "Slightly projecting from a surface" , "Self-respecting or self-important" , "Self-satisfied - stately - protruding" , "Feeling self-respect - projecting from a surface" .)