It doesn't take long to provide a deficiency (5,6)

I believe the answer is:

short supply

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'a deficiency' is the definition.
The answer and definition are not the same part of speech.

'it doesn't take long to provide' is the wordplay.
'it doesn't take long' becomes 'short' (I can't justify this - if you can you should believe this answer much more).
'to' means one lot of letters go next to another.
'provide' becomes 'supply' (synonyms).
'short'+'supply'='SHORT SUPPLY'

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

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