Eke out for a while (7)

I believe the answer is:

stretch

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

I don't understand how the remainder of the clue works.

(Other definitions for stretch that I've seen before include "Prison sentence (colloquial)" , "Period of time in prison" , "extended" , "Pull to make longer or wider" , "Exercise - period" .)

I've seen this clue in the Evening Standard.

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