desuetude

Desuetude must be closely related to "disuse," right? Wrong. Despite the similarities between them, "desuetude" and "disuse" derive from two different Latin verbs. Desuetude comes from "suescere," a word that means "to accustom" (it also gave us the word custom). "Disuse" descends from "uti," which means "to use" (that Latin word also gave us "use" and "utility"). Of the two, "disuse" is now the more common. "Desuetude" hasn't fallen into desuetude yet, and it was put to good use in the past, as in the 17th-century writings of Scottish Quaker Robert Barclay, who wrote, "The weighty Truths of God were neglected, and, as it were, went into Desuetude."