A deviation or divergence from appropriate conduct or dress; a departure from expected behavior.
From 'garde' (keeping, from French/Germanic roots, as in 'garderobe') plus 'deviance' (from Latin 'deviare,' meaning 'to turn aside'). This appears to be a rare or archaic compound.
This word is so obscure that it barely appears in historical texts—it seems to be a theoretical back-formation from 'gardedeviance,' showing how English tries to create words that follow its patterns even when nobody actually uses them.
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