Words That Rhyme With "Flattened" :
2 syllables:
bacchant, battement, batten, bracken, brightened, buttoned, cottoned, craton, fatten, fattened, frightened, gatten, Grattan, gratton, hadden, hadn't, happen, happened, heightened, machen, macken, madden, maddened, paten, patent, Paton, patten, Patton, ratton, sadden, saddened, saltant, staten, straightened, sweetened, tappan, threatened, tightened, whitened
3 syllables:
attractant, combatant, contactant, extractant, manhattan, mayhappen, Mcfadden, Mountbatten, Nevadan, reactant, surfactant, unbuttoned, unwhitened