Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
prompto, āre, v. freq. a. [promo], to give forth or out abundantly, to distribute, dispose of a thing (Plautin.): thesauros Jovis, i. e. to be Jupiter’s treasurer, Plaut. Ps. 2, 2, 33: illum meum malum promptare malim quam peculium, to have the disposal of, id. Bacch. 3, 3, 61.