3 syllables:
skillfully, visibly, timpani, symphony, synchrony, visually, tiffany, tinselly, whiffletree, infamy, flippancy, stringency, sympathy, viciously, wicopy, timothy, willowy, stickily, dittany, signally, wiggly, ministry, fixity, fidgety, instantly, vividly, filigree, brilliancy, litany, spitefully, symmetry, trilogy, brilliantly, stingily, finicky, trinity, brittany, imagery, instancy, villainy, bigotry, dismally, industry, fiscally, wilfully, flippantly, bigamy, dingily, mistily, rickety, dignity, willfully, tripoli, whippletree, differently, finitely, timidly, minutely, sicily, swingletree, infancy, piquancy, italy, syncope, chivalry, infantry, giddily, dizzily

4 syllables:
polygyny, proclivity, sufficiently, futility, viscidity, magistracy, benignancy, proficiency, facsimile, hostility, captivity, vicinity, gravimetry, torridity, indignity, salinity, antiquity, malignancy, publicity, invisibly, contingency, auspiciously, virility, utility, implicitly, solidity, resiliency, rigidity, liquidity, acidity, obstinately, rapidity, perniciously, tumidity, vapidity, aridity, astringency, toxicity, fluidity, humidity, timidity, turbidity, fragility, civility, antistrophe, ambitiously, affinity, antipathy, deficiency, spasticity, officially, cyclicity, initially, fertility, complicity, delinquency, sapidity, sweet cicely, asynchrony, polyphony, senility, deliciously, infinity, torpidity, epiphany, soliloquy, docility, ability, simplicity, religiously, flaccidity, abysmally, pasigraphy, miserably, polygamy, tepidity, avidity, growth industry, limpidity, felicity, antigone, sufficiency, explicitly, turgidity, festivity, placidity, literally, activity, immorally, consistently, liberally, tonicity, validity, mobility, prolixity, amphictyony, sphericity, culicidae, agility, somniloquy, viridity, nobility, ductility, asymmetry, consistency, propitiously, morbidity, efficiency, debility, divinity, nativity, epitome, efficiently, calligraphy, exigency, irritably, adamantly, adequacy, adequately, advocacy, allogamy, antiphony, appetency, canistel tree, casually, casualty, fashionably, fatuously, flatulency, laparoscopy, maximally, nationally, palatably, passionately, practicably, practically, rambutan tree, rationally, ravenously, salmagundi

5 syllables:
intermittency, self-sufficiency, cucurbitaceae, alkalimetry, expeditiously, inauspiciously, exiguity, insufficiency, contractility, eccentricity, insufficiently, conditionally, relativity, creativity, unofficially, alkalinity, surreptitiously, masculinity, meretriciously, inefficiency, atonicity, originally, pellucidity, probability, supersymmetry, elasticity, domesticity, artificially, conductivity, injudiciously, volatility, holy trinity, deliberately, ellipticity, legibility, negativity, versatility, invalidity, infelicity, peripherally, catholicity, additionally, electricity, insipidity, intrepidity, femininity, inutility, calorimetry, feasibility, aborigine, inconsistency, chromaticity, promiscuously, viability, fortuitously, traditionally, service industry, flexibility, possibility, productivity, irresistibly, inefficiently, unchristianly, specificity, avariciously, reactivity, colorimetry, capability, selectivity, compassionately, extravagantly, grammatolatry, inadequately, inhabitancy, intransigency, irrationally, miraculously, peace advocacy, recalcitrancy, unanimously, unfashionably, unpalatably, war advocacy

6 syllables:
compatibility, radial symmetry, idiosyncrasy, invisibility, superciliously, susceptibility, reliability, individually, amiability, unequivocally, periodicity, muscular dystrophy, availability, chemical industry, malleability, apocynaceae, perfectibility, joint probability, acceptability, mental deficiency, neuropsychiatry, responsibility, public utility, applicability, irritability, adaptability, palatability, unconditionally, admissibility, insensitivity, ignominiously, combat casualty, internationally, pusillanimously

7 syllables:
superconductivity, juvenile delinquency, inaccessibility, sexual activity, relative humidity, bioelectricity, bilateral symmetry, anthropocentricity, comprehensibility, hydroelectricity, irresponsibility, radioactivity, lactobacillaceae, static electricity, automobile industry, photoconductivity, special relativity, thermoelectricity, equipment casualty, personnel casualty

8 syllables:
theory of relativity, general relativity, piezoelectricity

9 syllables:
atmospheric electricity, operational casualty, unavoidable casualty