Code of silence customer tacitly keeps (6)

I believe the answer is:

omerta

'code of silence' is the definition.
(code of silence in the Mafia)

'customer tacitly keeps' is the wordplay.
'keeps' indicates the answer is hidden within the clue.
'OMERTA' can be found hidden inside 'customer tacitly'.

(Other definitions for omerta that I've seen before include "Mafia code of silence, never inform" , "Mafia pledge of silence" , "vow of silence" , "Mafia code of silence; at Rome (anag.)" , "conspiracy of silence" .)

I've seen this clue in The Times.

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