mis·us·er I. \(ˈ)mi|shüzə(r), (ˈ)mis|yüz-\noun Etymology:misuse (I) + -er : one that misuses < these wretched misusers of language — S.T.Coleridge > II. noun Etymology: Anglo-French, from Old French mesuser to misuse : an unlawful use of a right; especially: an unlawful use of a public office or grant of authority