Nonplussed rhymes with:
blust, lust, adjust, antitrust, blust, brust, bused, bussed, bust, clevetrust, combust, crust, cussed, discussed, disgust, distrust, dust, encrust, entrust, fussed, fust, gust, guste, hust, incrust, just, knust, lust, mistrust, must, prust, readjust, robust, rust, thrust, trust, unadjust, unjust, ustrust, yust