Does it get your foot accustomed to wearing it? (7)

I believe the answer is:

trainer

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'it get your foot accustomed to wearing it?' is the definition.
The definition suggests a singular noun which matches the answer.

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(Other definitions for trainer that I've seen before include "Coach; shoe" , "Footwear singularly" , "The odd thing an athlete may leave behind" , "one that helps runner perform" , "Sports coach" .)

I've seen this clue in the Evening Standard.

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