Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
mōmentānĕus, a, um, adj. [momentum], short, of brief duration, momentary (eccl. Lat.): momentaneus ardor gentium, Tert. adv. Marc. 3, 17 dub.: vices rerum, Ambros. Ep. 2, 24 init.: felicitas, Fulg. Myth. 2, 17; Hier. Ep. 69 (83), 9; Vulg. 2 Cor. 4, 17.