Swinger helps to pass the time (8)

I believe the answer is:

pendulum

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'swinger' is the definition.
(something which swings)

I don't understand the remainder of the clue.

(Other definitions for pendulum that I've seen before include "Nude lump (anag)" , "Oscillating part of clock" , "Swinging part of clock" , "A swinging weight as in old clock" , "It swings from side to side - in a clock?" .)

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

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