Unitarian rhymes with:
humanitarian, authoritarian, egalitarian, humanitarian, proletarian, utilitarian, vegetarian, authoritarian, egalitarian, humanitarian, lauretarian, libertarian, majoritarian, nonsectarian, parliamentarian, proletarian, sectarian, terrien, totalitarian, utilitarian, vegetarian
Unitarian sounds like:
unadorn, underarm, underman, undermine, unitrin, unterman