Cuts down on waste with unfortunate realisations (12)

I believe the answer is:

rationalises

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

'cuts' is the definition.
(I know this)

'down on waste with unfortunate realisations' is the wordplay.
'realisations' can be anagrammed to 'RATIONALISES'.
Though, I'm unsure how this is indicated.

Can you help me to learn more?

I've seen this clue in The Everyman puzzle in The Observer.

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