Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
prŏbābĭlĭtas, ātis, f. [probabilis], probability, credibility (class.): magna, Cic. Ac. 2, 24, 75: captiosa, id. Fin. 3, 21, 72: quodcumque nostros animos probabilitate percussit, id dicimus, id. Tusc. 5, 11, 33.