Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
impassĭbĭlis (inp-), e, adj. [2. in-passibilis], incapable of passion, passionless (eccl. Lat.): deus, Lact. 1, 3, 23; Tert. Apol. 10; Prud. Apoth. 84.
Adv.: impassĭbĭ-lĭter, without passion, Cassiod. Hist. Eccl. 3, 20; 5, 34.