Trump’s one calumny upset NBC, heading off the stars (4-5)

'trump's' is the definition.
Both the definition and answer are singular nouns.
Maybe you can see a link between them that I can't see?

'one calumny upset nbc heading off the stars' is the wordplay.
'one calumny' becomes 'mud' (mud is a kind of calumny).
'upset' is a reversal indicator.
'heading off' means to remove the first letter.
'the stars' becomes 'luck' (I can't explain this - if you can you should believe this answer much more).
'mud' back-to-front is 'dum'.
'nbc' with its initial letter taken off is 'bc'.
'dum'+'bc'+'luck'='DUMB-CLUCK'

Can you help me to learn more?