Lightfast rhymes with:
belfast, colorfast, holdfast, steadfast, superfast, amcast, belfast, broadcast, bypassed, chloroplast, colorfast, comcast, downcast, enthusiast, flabbergast, forecast, holdfast, iconoclast, newscast, outcast, outclassed, outlast, overcast, pendergast, polycast, prendergast, qualcast, rebroadcast, sandblast, simulcast, steadfast, superfast, telecast, tillinghast, triplecast, typecast