2 syllables:
featness, fleetness, meetness, neatness, sweetness

3 syllables:
completeness, concreteness, discreetness, discreteness, licitness, petiteness, repleteness, unmeetness

4 syllables:
bittersweetness, incompleteness, indiscreetness, np-completeness, obsoleteness, showing neatness

5 syllables:
turing completeness

2 syllables:
bleakness, cheapness, deepness, meekness, preakness, reedmace, sleekness, steepness, weakness

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, obliqueness, uniqueness

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

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