Unpopular rhymes with:
popular, popular, popular, angular, annular, avuncular, binocular, cardiovascular, cellular, circular, curricular, equiangular, extracurricular, gastrovascular, globular, granular, intercellular, intermolecular, irregular, jocular, jugular, molecular, muscular, particular, perpendicular, popular, rectangular, regular, secular, semicircular, singular, spectacular, testicular, triangular, tubular, unicellular, unspectacular, vascular, vehicular, vernacular