Softer rhymes with:
after, airlifter, drafter, drifter, hefter, hereafter, laughter, lenscrafter, lifter, rafter, shifter, shoplifter, snifter, stifter, swifter, telecrafter, thereafter, weightlifter, woofter
Softer sounds like:
saavedra, sabedra, saboteur, savedra, sceptre, septer, shifter, software, spadaro, spader, spataro, spatter, speeder, speedier, spider, spiteri, spotter, sputter, swifter