Duplicity rhymes with:
multiplicity, multiplicity, authenticity, ethnicity, multiplicity, synchronicity, adversity, authenticity, cassetty, cassity, ethnicity, mendacity, multiplicity, nicety, pomposity, propensity, reciprocity, scarcity, synchronicity, tenacity, varsity, veracity, virtuosity
Duplicity sounds like:
deflect, deflected, divulged, duplicate, duplicated