Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
rē-stĭpŭlor, āri, v. dep. a., to stipulate, promise, or engage in return (syn.: recipio, despondeo), Cic. Rosc. Com. 13, 38; App. Mag. p. 338, 25; Val. Max. 2, 8, 2.