Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sententĭōsē, adv., v. sententiosus fin.
sententĭōsus, a, um, adj. [sententia, II. B. 2.], full of meaning, pithy, sententious (rare but Ciceron.): sententiosum et argutum genus dictionis, Cic. Brut. 95, 325.
Adv.: sententĭōsē.