2 syllables:
vileness

3 syllables:
impetus, sinfulness, impotence, blissfulness, willfulness, imminence, synchronous, pythoness, vigilance, innocence, winsomeness, fistulous, minuteness, wickedness, nicholas, ninepence, bibulous, singleness, nimbleness, listlessness, synthesis, littleness, insolence, diligence, fickleness, ricinus, syllabus, dissonance, dictamnus, incidence, stimulus, immanence, diclinous, diffidence, limitless, frivolous, mischievous, singultus, spitefulness, mindlessness, skillfulness, instruments, simpleness, vividness, villainous, alikeness, wistfulness, brittleness, limulus, infamous

4 syllables:
infiniteness, calyculus, vertiginous, polygamous, indigenous, meticulous, deliciousness, officiousness, ridiculous, religiousness, antithesis, precipitance, equivalence, saint nicholas, asynchronous, maliciousness, leviticus, capriciousness, cuniculus, bicephalous, omnipotence, pediculus, perniciousness, felicitous, ambivalence, acidulous, utriculus, iniquitous, propitiousness, suspiciousness, nonsynchronous, declivitous, funiculus, auspiciousness, ambitiousness, adequateness, affableness, amphitropous, animateness, anthophilous, astragalus, calcicolous, caliculus, catalysis, fatuousness, gradualness, maleficence, passionateness, ranunculus, ravenousness, saxicolous, scandalousness, talentlessness, tangibleness, tractableness

5 syllables:
telekinesis, meretriciousness, indefiniteness, canaliculus, diakinesis, chemosynthesis, irreligiousness, inauspiciousness, geosynchronous, infelicitous, aspergillosis, unambiguous, compassionateness, dispassionateness, inadequateness, inanimateness, intangibleness, intractableness, invaluableness, magnanimousness

6 syllables:
angle of incidence, australopithecus, conditioned stimulus, autocatalysis, oleaginousness, pusillanimousness