Lewis & Short

ūmĕ-făcĭo (less correctly hū-), no perf., factum, ĕre, 3, v. a. [umeo-facio], to make moist, to moisten, wet (post-class.): de halitu terrae aut maris nebula exsistit, quae dispersa umefacit, quicquid texerit, Lact. de Ira Dei, 10: spongia crebro umefacta, Plin. 32. 10, 48, § 138.