Make well, perhaps, with exercise (5)

I believe the answer is:

drill

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'exercise' is the definition.
(I know that exercise can be written as drill)

I don't understand the rest of the clue.

(Other definitions for drill that I've seen before include "Training (to make holes?)" , "boring one" , "strong twilled cotton" , "Military training; bore" , "Square-bashing" .)

I've seen this clue in The Irish News.

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