Lewis & Short

ĭn-ăcesco (also inăcisco), ăcŭi, 3, v. inch. n., to become sour in any thing, to turn sour (perh. not ante-Aug.).

  1. I. Lit.: lac, Plin. 28, 9, 36, § 135: quibus frequenter inacescit cibus, Scrib. Comp. 104.
  2. II. Trop.: haec tibi per totos inacescant omnia sensus, let them sour. i. e. imbitter you, Ov. R. A. 307; cf.: si tibi inacuit nostra contumelia, App. M. 5, p. 163, 23.