Fasts rhymes with:
blasts, castes, casts, forecasts, lambastes, last's, lasts, masts, nast's, pasts
Fasts sounds like:
facades, facet's, facetious, facets, factitious, facts, fajitas, fascists, fastidious, faucets, faught's, faustus, feasts, fests, festus, fictitious, fight's, fights, fists, fixates, fojtik, fosdick, fossett's, foxwoods, fujitsu, fujitsu's, fustok