Contrite worker shut up again (9)
I believe the answer is:
repentant
'contrite' is the definition.
(similar in meaning)
'worker shut up again' is the wordplay.
I cannot really see how this works, but
'worker' could be 'ant' (worker is a type of ant) and 'ant' is located in the answer.
'again' could be 're' (prefix meaning 'again') and 're' is located in the answer.
'shut up' could be 'pent' (synonyms) and 'pent' is found within the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for repentant that I've seen before include "Regretful" , "showing contrition" , "sorry state" , "Contrite" , "Feeling remorse for misdeeds" .)