Calamitous rhymes with:
fremitus, emeritus, equitas, felicitous, fremitus, gratuitous, gravitas, hippolytus, impetus, prophetess, riotous, solicitous
Calamitous sounds like:
calamities, calmat's, claimants, claimants', clematis, clemente's, clementes, clements, clementz, client's, clients, clients', climates, climatic, clonts, clontz, coolants, culminates