Grump rhymes with:
crump, frump, rump, trump, bump, chump, clump, crump, dump, frump, gump, gumpp, hump, jump, klump, klumpp, kump, lump, lumpp, plump, pump, rump, slump, stump, stumpe, stumpp, sump, thump, trump
Grump sounds like:
granoff, greenup, grownup, grumpy