Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dis-pesco (pescui, acc. to Prisc. p. 885 P.), pestum, 3, v. a. [commonly referred to pasco; lit., to take from the pasture (pecus a pastione deducere, Paul. ex Fest. p. 72, 11), but more probably from root pac-, παγ- of Gr. πήγνυμι, to fasten; Lat.: pango, paciscor, etc.; cf. Curt. Gr. Etym. 268], like disjungere, in gen.,