Relapses rhymes with:
collapses, lapses, collapses, lapses, collapses, cyclops's, eclipses, glimpses, lapses, phelps's, philips's, phillips's, synapses
Relapses sounds like:
railbike, ralph's, ralphs, relapse, reliefs, relieves, roelofs, rohlfs, rolfes, rolfs, rollback, rollbacks, rulebook