Crossword Genius

You will know when you've got it (9)

Ross

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8

9

erudition

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'you will' is the definition.
The answer and definition can be both related to thinking as well as being singular nouns.
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(Other definitions for erudition that I've seen before include "Knowledge, learning" , "State of learning or culture" , "Great knowledge" , "Great learning" , "being widely read" .)

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