Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Mŭtusca, ae, f., = Trebula Mutusca, a city in the Sabine territory: olivifera, Verg. A. 7, 711. Its inhabitants are called Trēbŭlāni Metusci, Plin. 3, 12, 17, § 107; v. Trebula.