Like Quixote - at it about fifty! (5)

I believe the answer is:

atilt

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'like quixote at it about fifty' is the definition.
I can't judge whether this definition defines the answer.

'at it about fifty' is the wordplay.
'about' is an insertion indicator.
'fifty' becomes 'l' (Roman numeral).
'it' enclosing 'l' is 'ilt'.
'at'+'ilt'='ATILT'

Can you help me to learn more?

(Other definitions for atilt that I've seen before include "not quite horizontally" , "Leaning over and nearly falling" , "Inclined" , "Pulled tight" , "Listing" .)

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

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