Prompt to receive posh noble (5)
I believe the answer is:
proud
'noble' is the definition.
(thesaurus)
'prompt to receive posh' is the wordplay.
'prompt' becomes 'prod'.
'to receive' means one lot of letters goes inside another.
'posh' becomes 'u' (abbreviation for upper-class - opposite to non-u).
'prod' placed around 'u' is 'PROUD'.
(Other definitions for proud that I've seen before include "Walking tall" , "Having a high opinion of oneself" , "Boastful" , "Haughty; projecting a little" , "Conscious of one's own dignity" .)