Constancy rhymes with:
inconstancy, inconstancy, inconstancy, consistency, inconsistency, inconstancy, accountancy, consistency, consultancy, expectancy, hesitancy, incompetency, inconsistency, inconstancy, latency, militancy, potency
Constancy sounds like:
coincidence, coincidences, coinciding, communicating, communication's, communications, communications', conceding, concocting, concoctions, conjugations, connecting, connections, consistence, consistency, consisting, constance, constituencies, constituency, constituting, constitution's, constitutions