A rare or obsolete abbreviation or shortened form of furniture or furnishment.
From furniture or furnish, abbreviated through colloquial use or shorthand, similar to how 'prep' comes from 'prepare' or 'lab' from 'laboratory.'
Furnit is one of those delightful dead words that makes us realize how much language changes—abbreviated forms only survive if they become genuinely useful, and furnit apparently wasn't useful enough to stick around.
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