Flenniken rhymes with:
hanneken, cormican, hanneken, ketchikan, litteken, melican, millican, milliken, mullican, mulliken, new-mexican, ratican, republican, sippican, transamerican, unamerican, vatican
Flenniken sounds like:
fillingame, fillingham, fillingim, flamson, flanagan, flanagin, flanigan, flannagan, flannigan, flinchum