desuetude

Origin

From Late Middle English desuetude, dissuetude (“discontinuance of a practice, disuse”), from Middle French désuétude (“obsolescence”) (modern French désuétude), from Latin dēsuētūdo (“discontinuance of a practice or a habit, disuse”), from dēsuētus + -tūdō (“suffix forming abstract nouns indicating conditions or states”). Dēsuētus is the perfect passive participle of dēsuēscō (“to make unaccustomed”), from de- (prefix having a reversing or undoing effect) + suēscō (“to become accustomed or used to; (Late Latin) to accustom, habituate, train”) (ultimately from Proto-Indo-European *swé (“self”) + *dʰeh₁- (“to do; to place, put”), in the sense “to set as one’s own”).