Suppressed author set to return (4-2)
I believe the answer is:
pent-up
'suppressed' is the definition.
(I've seen this in another clue)
'author set to return' is the wordplay.
'author' becomes 'pen' (to pen something is to author it).
'set' becomes 'put' (synonyms).
'to return' says the letters should be written backwards.
'put' reversed gives 'tup'.
'pen'+'tup'='PENT-UP'
(Other definitions for pent-up that I've seen before include "Confined like dam water or suppressed anger" , "Russian city" , "Repressed, emotions say" , "Held back, confined" , "Closely confined" .)