Party hard? I've been foolish! (3)

I believe the answer is:

doh

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'i've been foolish' is the definition.
I can't judge whether this defines the answer.

'party hard?' is the wordplay.
'party' becomes 'do' (do is a kind of party).
'hard?' becomes 'h' (abbreviation used in pencil classifications).
'do'+'h'='DOH'

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(Other definitions for doh that I've seen before include "Note; exclamation" , "annoyed expression" , "Homer Simpson's exasperated cry" , "First and eighth note in tonic sol-fa" , "whoops!" .)

I've seen this clue in The Independent.

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