3 syllables:
-cephaly, cephaly

4 syllables:
acephaly, dicephaly

5 syllables:
acrocephaly, anencephaly, autocephaly, brachycephaly, cebocephaly, clinocephaly, colpocephaly, cyclocephaly, cymbocephaly, cynocephaly, exencephaly, hydrocephaly, hypsicephaly, isocephaly, lissencephaly, macrencephaly, macrocephaly, megacephaly, mesocephaly, microcephaly, nanocephaly, orthocephaly, otocephaly, oxycephaly, platycephaly, polycephaly, porencephaly, rhinocephaly, scaphocephaly, schizencephaly, sclerencephaly, tectocephaly, turricephaly

6 syllables:
dolichocephaly, hydranencephaly, iniencephaly, macroencephaly, megalocephaly, mesaticephaly, microencephaly, plagiocephaly, trigonocephaly

7 syllables:
holoprosencephaly, hydromicrocephaly

3 syllables:
skillfully, visibly, timpani, symphony, synchrony, visually, tiffany, tinselly, whiffletree, infamy, flippancy, stringency, sympathy, viciously, wicopy, timothy, willowy, stickily, dimity, 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, benghazi, bestially, breathlessly, brevity, centrally, chemically, chemistry, clemency, credibly, density, deputy, desperately, destiny, devilry, dextrously, dreadfully, ebony, ecstasy, ectropy, elegy, embassy, emigree, empathy, endlessly, enemy, enmity, entity, entropy, equity, evilly, fecklessly, federally, felony, flexibly, gemini, generally, heavenly, heavily, helpfully, helplessly, jealously, jealousy, jejunely, kennedy, legacy, legatee, legibly, lemony, lengthily, lenity, leprosy, medically, melanie, melody, mentally, peasantry, pebbly, pedantry, pederasty, pedigree, penally, penalty, pleasantly, pleasantry, preciously, preferably, pregnancy, presently, readily, recipe, remedy, resiny, restfully, revelry, secondly, self-pity, selflessly, senselessly, sensibly, sentiency, separately, sesame, seventy, severally, specially, specialty, splendidly, steadily, stephanie, tenancy, tenantry, tendency, tensity, tentatively, tepidly, testily, threnody, trenchancy, trepidly, velvety, venally, vengefully, weaponry, yemeni, zealotry, zestfully, zestily

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, proximity, 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, acceptably, allegedly, amenity, anemone, ascendancy, ascendency, complexity, confederacy, confessedly, contemptuously, convexity, death penalty, defencelessly, dependency, detestably, discrepancy, domenici, especially, essentially, eventually, exceptionally, expectancy, extremity, fidelity, flux density, forelady, hegemony, heredity, identity, illegibly, immensity, impendency, impetuously, incessancy, incessantly, inclemency, incredibly, indemnity, ineffably, inequity, infectiously, inflexibly, insensibly, integrity, intensity, intrepidly, jack kennedy, lamentably, licentiously, lieutenancy, lobectomy, longevity, low density, lumpectomy, mastectomy, necessity, nephrectomy, neurectomy, nonentity, ostensibly, penelope, perceptibly, perplexedly, perplexity, polemically, potentially, pretentiously, professedly, professionally, quiescency, rebelliously, refreshfully, regrettably, relentlessly, repentantly, respectably, respectfully, resplendency, resplendently, revengefully, schenectady, sententiously, sequentially, serenity, shell entity, solemnity, splenectomy, successfully, supremacy, telemetry, telepathy, thrombectomy, transcendency, tremendously, unhelpfully, unpleasantly, unsteadily, vasectomy, vulvectomy, with empathy

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, magnanimity, ellipticity, legibility, negativity, versatility, invalidity, infelicity, peripherally, catholicity, additionally, electricity, insipidity, intrepidity, femininity, inutility, calorimetry, feasibility, aborigine, inconsistency, chromaticity, unanimity, promiscuously, viability, fortuitously, traditionally, service industry, flexibility, possibility, productivity, irresistibly, inefficiently, unchristianly, specificity, avariciously, reactivity, colorimetry, capability, selectivity, accidentally, appendectomy, biochemistry, change integrity, change intensity, coalescency, conscientiously, consequentially, create mentally, deferentially, detrimentally, disrespectfully, drunken revelry, embolectomy, field intensity, fundamentally, geochemistry, half-intensity, high-fidelity, high fidelity, hysterectomy, incidentally, independency, independently, intumescency, laminectomy, laryngectomy, life expectancy, line of destiny, mask of pregnancy, mastoidectomy, meniscectomy, mortal enemy, mountain ebony, naval weaponry, of necessity, oophorectomy, open sesame, orchidectomy, orchiectomy, penitentially, photochemistry, pneumonectomy, prostatectomy, providentially, reprehensibly, reverentially, rhytidectomy, salpingectomy, school of dentistry, sentimentally, sigmoidectomy, stapedectomy, sympathectomy, thyroidectomy, tonsillectomy, tubal pregnancy, unacceptably, unforgettably, unintentionally, unpretentiously, unrepentantly, unsuccessfully, vapor density, white supremacy

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, pusillanimity, irritability, adaptability, palatability, unconditionally, admissibility, insensitivity, ignominiously, adenoidectomy, adrenalectomy, anas penelope, appendicectomy, change of integrity, cholecystectomy, coincidentally, cosmetic dentistry, electrochemistry, environmentally, experimentally, genus penelope, immunochemistry, inconsequentially, interdependency, manifest destiny, militant tendency, organic chemistry, ovariectomy, panhysterectomy, pedal extremity, physical chemistry, radiochemistry, relative density, simple mastectomy, unsentimentally

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, abdominal pregnancy, department of chemistry, executive clemency, feeling of identity, inorganic chemistry, john fitzgerald kennedy, magnetic flux density, magnetic intensity, ovarian pregnancy, radical mastectomy, suprarenalectomy, total hysterectomy

8 syllables:
theory of relativity, general relativity, piezoelectricity, conformational entropy, interpersonal chemistry, radical hysterectomy

9 syllables:
atmospheric electricity

10 syllables:
modified radical mastectomy