Strict about toilet? She won't be! (8)

I believe the answer is:

slattern

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'she won't be' is the definition.
I can't tell whether this definition defines the answer.

'strict about toilet?' is the wordplay.
'strict' becomes 'stern' (I've seen this before).
'about' is an insertion indicator.
'toilet?' becomes 'lat' (short for latrine).
'stern' enclosing 'lat' is 'SLATTERN'.

Can you help me to learn more?

(Other definitions for slattern that I've seen before include "Slovenly woman" , "Slovenly person" , "Rent last (anag) - slut" , "Dirty and untidy woman" , "Sloven" .)

I've seen this clue in The Independent.

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