Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
caupōnor, āri, v. dep. [caupo], to traffic or trade in any thing; trop.: bellum, Enn. ap. Cic. Off. 1, 12, 38 (Ann. v. 201 Vahl.); cf. the Gr. καπηλεύειν μάχην, Aesch. Sept. 347: verbum veritatis, Cassiod. Hist. Eccl. 4, 24.