Tolerate having grass on that garment (7)

I believe the answer is:

singlet

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'that garment' is the definition.
(singlet is a kind of garment)

I can't explain the rest of the clue.

(Other definitions for singlet that I've seen before include "Tingles in vest" , "Sleeveless vest" , "Underwear" , "Something to wear" , "One unaccompanied" .)

I've seen this clue in The Telegraph.

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