Says it's kept here, on the left, for religious adherent (4)

I believe the answer is:

sikh

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'religious adherent' is the definition.
(I've seen this before)

I can't explain the remainder of the clue.

(Other definitions for sikh that I've seen before include "Religious follower" , "An adherent of religion founded in the Punjab" , "Member of an Indian religion" , "Pardon (sin); send (money) in payment" , "Follower of gurus" .)

I've seen this clue in The Irish Times.

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