Squander brief daytime kip, getting maximally flushed? (9)

I believe the answer is:

blowsiest

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'brief daytime kip getting maximally flushed?' is the definition.
I can't tell whether this definition defines the answer.

'squander' is the wordplay.
I cannot really understand how this works, but
'squander' could be 'blow' (synonyms) and 'blow' is present in the answer.
This explanation may well be incorrect...

Can you help me to learn more?

I've seen this clue in The Independent.

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