3 syllables:
bigamy, bigotry, bishopry, brilliancy, brilliantly, brittany, chintzily, chivalry, differently, dignity, dingily, dismally, dittany, dizzily, filigree, filthily, finicky, fiscally, fixity, flindosy, flippancy, flippantly, frigidly, giddily, imagery, industry, infamy, infancy, infantry, instancy, instantly, italy, liberally, licitly, lingually, litany, literally, millime, ministry, minstrelsy, minutely, miserably, mistily, pipal tree, prissily, quizzically, ribbony, rickety, shittah tree, sicily, signally, simile, skilfully, skillfully, stickily, stingily, stringency, stringently, swingletree, symmetry, sympathy, symphony, synchrony, syncope, tiffany, timidly, timothy, timpani, tinselly, trickily, trilogy, trinity, tripoli, twinkly, viciously, villainy, viscidly, visibly, visually, vividly, whiffletree, whippletree, wiggly, wilfully, willfully, willowy, windily, winsomely, wriggly

4 syllables:
ability, abysmally, acclivity, acidity, acridity, activity, additionally, affinity, agility, ambitiously, antigone, antipathy, antiquity, aridity, arms industry, astringency, asymmetry, asynchrony, blessed trinity, calligraphy, captivity, civility, coal industry, complicity, conditionally, consistency, consistently, contingency, cyclicity, debility, declivity, deficiency, deliberately, deliciously, delinquency, divinity, docility, ductility, efficiency, efficiently, epiphany, epitome, exigency, explicitly, facsimile, felicity, fertility, festivity, film industry, fluidity, forgivably, fragility, futility, gelidity, growth industry, hostility, humidity, implicitly, indignity, infinity, initially, insistency, invisibly, limpidity, liquidity, malignancy, malignity, mendicancy, mobility, morbidity, motivity, nativity, nobility, officially, oil industry, originally, pasigraphy, peripherally, permissibly, persistency, persnickety, plasticity, polygamy, polygyny, polyphony, proclivity, proficiency, prolixity, propinquity, propitiously, proximity, publicity, put differently, rapidity, religiously, resiliency, rigidity, rusticity, salinity, sanguinity, sapidity, senility, shoe industry, sign industry, simplicity, solidity, soliloquy, somniloquy, spasticity, steel industry, stolidity, sufficiency, sufficiently, sweet cicely, tactility, tepidity, timidity, torpidity, toxicity, toy industry, traditionally, tumidity, turbidity, unthinkably, utility, validity, vapidity, ventriloquy, vicinity, viridity, virility, with sympathy

5 syllables:
aborigine, absorptivity, alkalinity, artificially, banking industry, calorimetry, capability, chondrodystrophy, chromaticity, colorimetry, concentricity, conductivity, consanguinity, contractility, creativity, domesticity, eccentricity, elasticity, electricity, expansivity, expeditiously, fashion industry, feasibility, femininity, flexibility, granadilla tree, holy trinity, housing industry, imbecility, impermissibly, inconsistency, inconsistently, individually, inefficiency, inefficiently, infelicity, inhospitably, insufficiency, insufficiently, intermittency, inutility, invalidity, irresistibly, legibility, lighting industry, masculinity, mass deficiency, mental imagery, mirror symmetry, movie industry, mutability, negativity, notability, perceptivity, plastics industry, possibility, probability, productivity, progressivity, quotability, reactivity, reflectivity, refractivity, relativity, reluctivity, resistivity, retentivity, risibility, sapodilla tree, selectivity, self-sufficiency, service industry, sex activity, specificity, stretchability, supersymmetry, surreptitiously, syllabicity, tangibility, taoist trinity, transitivity, trucking industry, unambitiously, unanimity, unconditionally, unequivocally, unforgivably, unofficially, unpredictably, unpropitiously, versatility, viability, volatility, without sympathy, with efficiency, with hostility, with validity, zinc deficiency

6 syllables:
acceptability, adaptability, admissibility, amiability, amicability, analyticity, antifertility, apparel industry, applicability, approachability, availability, business activity, chemical industry, commutability, compatibility, compressibility, computer industry, construction industry, contemptibility, correlativity, deductibility, despicability, digestibility, duplicability, equatability, excitability, higgledy-piggledy, human activity, idiosyncrasy, illegibility, immutability, impeachability, implausibility, improbability, incapability, inelasticity, infeasibility, inscrutability, insensibility, insensitivity, intangibility, intransitivity, invisibility, irritability, joint probability, latent hostility, learning ability, malleability, mental ability, mental deficiency, munitions industry, muscular dystrophy, palatability, perceptibility, permutability, practicability, public utility, radial symmetry, refining industry, reliability, reputability, responsibility, reversibility, semifluidity, shipbuilding industry, social activity, suggestibility, susceptibility, tobacco industry, unfeasibility, unsuitability

7 syllables:
aluminum industry, anthropocentricity, automobile industry, bilateral symmetry, bioelectricity, capital of italy, commercial activity, comprehensibility, current electricity, disreputability, doctor of divinity, electronics industry, entertainment industry, hydroelectricity, imperceptibility, imperishability, imperturbability, impracticability, inaccessibility, inadmissibility, inapplicability, incommutability, incompressibility, inconvertibility, indigestibility, indisputability, ineligibility, intelligibility, in all probability, irrepressibility, irresponsibility, irreversibility, juvenile delinquency, magical ability, master of divinity, natural ability, offensive activity, photoconductivity, physical ability, radial asymmetry, radioactivity, relative humidity, reprehensibility, securities industry, sensory activity, sexual activity, special relativity, static electricity, substitutability, subversive activity, superconductivity, thermoelectricity, unacceptability, unadaptability, unapproachability, unpalatability, unsusceptibility

8 syllables:
australian aborigine, bachelor of divinity, civic responsibility, dynamic electricity, general relativity, indistinguishability, intelligence activity, irrational hostility, performance capability, piezoelectricity, sense of responsibility, theory of relativity, unintelligibility

9 syllables:
atmospheric electricity, educational activity, military capability, operating capability

10 syllables:
coefficient of elasticity, conservation of electricity, extracurricular activity, special theory of relativity, without showing responsibility

11 syllables:
general theory of relativity