Part-time workers' clothing (7)

I believe the answer is:

casuals

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'clothing' is the definition.
(I have seen 'Informal clothing ' mean 'casuals' so perhaps 'clothing' could also mean 'casuals')

I cannot understand how the rest of the clue works.

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(Other definitions for casuals that I've seen before include "Footwear" , "Temps" , "informal wear" , "Temporary worker's" , "soccer hooligans" .)

I've seen this clue in The Irish Independent.

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