Give someone a sharp reminder (5)

I believe the answer is:

nudge

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

I can't explain the remainder of the clue.

(Other definitions for nudge that I've seen before include "Encouraging prompt" , "Gentle prod" , "A gentle reminder?" , "Remind (with the elbow?)" , "Remind, prompt gently" .)

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

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