Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
laetābĭlis, e, adj. [laetor], joyful, glad, gladsome (class.): quid habet ista res aut laetabile, aut gloriosum? Cic. Tusc. 1, 21, 49: nihil laetabile, id. ib. 4, 17, 37: factum, Ov. M. 9, 255: sidus alicui, Val. Fl. 6, 606.
Comp., Mamert. Genethl. 18.