Lewis Short
(adjective) : văpōrālis, e, vapor
* Of or belonging to steam or vapor, vapory (late Lat.): tenuitas,Aug. Genes. ad Lit. 2, 5.—Adv.: văpōrālĭter, like a vapor, Aug. Genes. ad Lit. 2, 4 fin.; 3, 10 fin.
Charlton T. Lewis, Charles Short, A Latin Dictionary