One may itch to do it (7)

I believe the answer is:

scratch

I'm a little stuck... Click here to teach me more about this clue!

'one may itch' is the definition.
'scratch' can be an answer for 'itch' (thesaurus). I'm unsure of the 'one may' bit.

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for scratch that I've seen before include "Insignificant injury" , "not much of a handicap" , "Score, mark; cancel" , "score with > no handicap given" , "Decide not to play" .)

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

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