Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
importābĭlis (inp-), e, adj. [2. inportabilis], that cannot be borne, insupportable; lit. and trop. (late Lat.), Tert. adv. Marc. 4, 27 med.: moenium arietes, Cassiod. Var. 7, 6: malum, id. ib. 9, 2 al.
Adv.: importābĭlĭter, in an insupportable manner: omnia contra eos facientes, Cassiod. Hist. Eccl. 7, 29.