Shut up and write a letter (4)

I believe the answer is:

pent

'shut up' is the definition.
(synonyms)

'write a letter' is the wordplay.
'write' becomes 'pen' (synonyms).
'a letter' becomes 't' ().
'pen'+'t'='PENT'

'and' acts as a link.

(Other definitions for pent that I've seen before include "enclosed" , "Closely confined" .)

I've seen this clue in The Globe and Mail.

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