Colossal rhymes with:
apostle, basile, docile, fossel, fossil, jostle, microfossil, possehl, postle, rossell, stossel, trostle, vasile
Colossal sounds like:
callously, ceaselessly, chalkley, classical, classically, clausell, cleckley, closely, coleslaw, collegial, colloquial, colossally, cyclical