Praise nobleman, say (4)
I believe the answer is:
laud
'praise' is the definition.
(I know that laud is a more specific form of the action praise)
'nobleman say' is the wordplay.
'nobleman' becomes 'lord' (synonyms).
'say' indicates a 'sounds like' (homophone) clue.
'lord' is a homophone of 'LAUD'.
(Other definitions for laud that I've seen before include "Praise, magnify" , "Praise formally" , "Praise, extol" , "Praise acclaim" , "Archbishop of Canterbury, executed 1645" .)