Onus rhymes with:
bonus, colonus, conus, cronus, jonas, keratoconus, kotsonis, kotsonis', monus, petronas, slowness
Onus sounds like:
oehmens, ohioans, ohm's, ohms, ohnemus, omaha's, omans, omega, omens, ominous, onassis, onassis', onassis's, once, one's, oneness, oneok, ones, ones', onex, onex's, ong, onions, onishi, ons, onyx, ounce, ounces, owen's, owens, owens's, owing, owings, owning, owns