Flattery can quietly lift (6)
I believe the answer is:
praise
'flattery' is the definition.
(thesaurus)
'quietly lift' is the wordplay.
'quietly' becomes 'p' (p for piano and quiet).
'lift' becomes 'raise' (synonyms).
'p'+'raise'='PRAISE'
'can' is the link.
(Other definitions for praise that I've seen before include "Congratulate" , "Be aware of (something)" , "Aspire (anag)" , "Extol, glorify" , "plaudit" .)