2 syllables:
alnus, falness

3 syllables:
fatalness, frugalness, localness, mortalness, vitalness

4 syllables:
centricalness, cubicalness, cynicalness, dropsicalness, factualness, generalness, genialness, lyricalness, musicalness, punctualness, rationalness, rusticalness, stoicalness, technicalness

5 syllables:
apocryphalness, authenticalness, congenialness, effectualness, extrinsicalness, fantastic-alness, heroicalness, illogicalness, impartialness, intrinsicalness, ironicalness, lethargicalness, materialness, mercurialness, organicalness, originalness, propheticalness, satiricalness, sporadicalness, tyrannicalness

6 syllables:
analogicalness, apostolicalness, idioticalness, ineffectualness

3 syllables:
emphasis, nebulous, elements, hephaestus, tetanus, sedulous, petulance, offenseless, fecklessness, membranous, restlessness, excellence, exodus, evidence, pendulous, recklessness, edifice, detritus, blessedness, helplessness, renascence, precedence, helpfulness, pestilence, tremulous, prevalence, eminence, tenebrous, fretfulness, aesculus, pegasus, endlessness, resinous, credulous, resonance, dreadfulness, elephants, eloquence, pleasantness, regulus, daedalus, gentleness, healthfulness, precipice, petalous, specialness, negligence, tendinous, tenuous, emulous, femaleness, genesis, xenopus, venomous, benelux, elegance, relevance

4 syllables:
contentiousness, benevolence, inelegance, antecedence, preeminence, beneficence, unpleasantness, affectedness, apetalous, directionless, edematous, shigellosis, state's evidence, maleficence, pink elephants, persepolis, incredulous, irrelevance, intelligence, malevolence, eleven-plus, necessitous, exophthalmos, monophthalmos

5 syllables:
macrocephalous, leptocephalus, atelectasis, conscientiousness, hearsay evidence, hydrocephalus, direct evidence, microcephalous, overemphasis

6 syllables:
magnetic resonance, indirect evidence, dicotyledonous

7 syllables:
circumstantial evidence

8 syllables:
artificial intelligence