3 syllables:
quiddity

4 syllables:
acidity, acridity, algidity, aridity, avidity, calidity, callidity, cupidity, fervidity, fixidity, flaccidity, floridity, fluidity, fulgidity, fumidity, gelidity, gravidity, hispidity, humidity, lanquidity, limpidity, liquidity, lividity, lucidity, marcidity, morbidity, pallidity, pavidity, pinguidity, placidity, prigidity, putidity, rabidity, rancidity, rapidity, rigidity, sapidity, solidity, squalidity, stolidity, tepidity, timidity, torpidity, trepidity, tumidity, turbidity, validity, vapidity, vastidity, viridity, viscidity, vividity

5 syllables:
anacidity, comorbidity, illiquidity, insolidity, invalidity, pellucidity, subacidity, with validity

6 syllables:
hyperacidity, hypoacidity, pseudorapidity, semiaridity, semifluidity, semiliquidity, superacidity, superfluidity

7 syllables:
relative humidity, semipellucidity

3 syllables:
gimmickry, whimsically, typically, filthily, fittingly, ministry, civilly, swimmingly, resignedly, trinity, imagery, hillbilly, principally, frigidly, trippingly, mimicry, wickedly, limpidly, impishly, willingly, rigidly, killingly, wittingly, realty, cliquishly, cryptically, dimity, fidgety, fishily, gibingly, lingeringly, pidlimdi, sickeningly

4 syllables:
exquisitely, sanguinity, tranquillity, terrifically, critically, vicinity, submissively, excitingly, befittingly, admittedly, plasticity, publicity, stability, tranquility, ethnicity, motility, acclivity, spheniscidae, derisively, affinity, sterility, benignity, fertility, complicity, ubiquity, motivity, scurrility, infinity, facility, linguistically, physically, declivity, simplicity, unwillingly, duplicity, cynically, obliquity, capriciously, puerility, activity, vindictively, incisively, sublimity, humility, judiciously, specifically, unwittingly, servility, indistinctly, gentility, virginity, mobility, tactility, iniquity, malignity, gracility, convincingly, passivity, assiduity, auspiciously, bewitchingly, forgivingly, long-windedly, pacifically, perniciously, sidesplittingly, tonicity, uncivilly, unthinkingly

5 syllables:
expansivity, refractivity, juvenility, immobility, receptivity, arability, objectivity, anonymity, absorptivity, audibility, movability, tangibility, durability, indecisively, realistically, concentricity, subjectivity, volubility, notability, suitability, portability, intrinsically, palpability, sensibility, pliability, mutability, gullibility, solubility, synchronicity, disability, affability, infertility, imbecility, unconvincingly, sociability, politically, sensitivity, transitivity, fallibility, curability, resistivity, visibility, tractability, credibility, inability, multiplicity, instability, longanimity, directivity, perceptivity, risibility, plausibility, friability, readability, unanimity, positivity, inactivity, serendipity, changeability, tenability, productivity, liability, edibility, equanimity, uncritically, culpability, authenticity, incivility, reflexivity, statistically, impassivity, altruistically, atonicity, avariciously, bendability, breakability, effectivity, egotistically, health facility, immotility, inauspiciously, injudiciously, magnanimity, meretriciously, obsessivity, pessimistically, provability, ratability, spinnability, squeezability, stainability, synonymity, taxability, unforgivingly

6 syllables:
admirability, compressibility, respectability, digestibility, variability, attainability, practicability, intangibility, irascibility, incredibility, predictability, tax liability, dependability, amicability, optimistically, separability, impalpability, antifertility, scientifically, inscrutability, profitability, suggestibility, impossibility, hyperactivity, serviceability, infallibility, transferability, availability, permeability, convertibility, corruptibility, navigability, invincibility, transmutability, sustainability, accessibility, vulnerability, agreeability, insensibility, intransitivity, incurability, demonstrability, inflexibility, excitability, alterability, replaceability, characteristically, dissolubility, inaudibility, contemptibility, desirability, advisability, unrealistically, adorability, commutability, reversibility, incapability, immovability, penetrability, eligibility, intractability, infeasibility, insolubility, formidability, perdurability, manageability, illegibility, destructibility, immutability, amenability, improbability, comparability, perceptibility, conceivability, unsociability, impregnability, exchangeability, achievability, answerability, assailability, believability, delectability, discernability, dispensability, docking facility, inculpability, indictability, interactivity, marriageability, measurability, noticeability, overactivity, penal facility, perfectability, perfectibility, permissibility, rateability, transposability, unchangeability

7 syllables:
understandability, inadmissibility, inapplicability, incommutability, imperceptibility, intelligibility, incompatibility, impenetrability, inexorability, invariability, indigestibility, indestructibility, imperishability, associability, substitutability, photosensitivity, unpredictability, interchangeability, invulnerability, quantifiability, ineligibility, maneuverability, irreversibility, inevitability, reproducibility, athletic facility, companionability, imperfectibility, impermeability, impermissibility, inadvisability, inconceivability, incorruptibility, indispensability, indomitability, indubitability, manipulability, unalterability, unavailability, uncharacteristically, undependability, undesirability, unexchangeability, unmalleability, unprofitability, unquestionability, unreliability, unrespectability

8 syllables:
incontrovertibility, radiosensitivity, limited liability, indefatigability, incomprehensibility, irreproducibility

9 syllables:
recreational facility