3 syllables:
density, tensity

4 syllables:
dimensity, extensity, flux density, high-density, immensity, low-density, low density, perpensity, propensity, protensity

5 syllables:
double-density, half-intensity, teledensity, vapor density

6 syllables:
hyperintensity, radiodensity, relative density

7 syllables:
magnetic flux density

2 syllables:
thessaly

3 syllables:
registry, severally, splendidly, pleasantly, messily, jestingly, levity, tendency, ebony, pedigree, credibly, gemini, venally, leprosy, prelacy, lengthily, elegy, readily, tenantry, weaponry, helplessly, equity, zestfully, deviltry, remedy, breathlessly, brevity, revelry, devisee, flexibly, melody, steadily, entity, jealousy, restfully, enemy, seventy, entropy, peasantry, clemency, velvety, lenity, pleadingly, negligee, threnody, sensibly, devilry, self-pity, chemistry, pedantry, selfishly, pregnancy, legacy, bestially, cecity, necropsy, sesame, dentistry, zealotry, mentally, dreadfully, helpfully, testily, emily, specially, embassy, tenancy, pleasantry, centrally, effigy, kennedy, deputy, secondly, enmity, legatee, felony, preciously, recipe, ecstasy, especially, debauchee, ethnically, specialty, presently, destiny, heavily, heavenly, medically, endlessly, empathy, jealously, helsinki, chemically, penalty, legibly, benghazi, dextrously, ectropy, emigree, evilly, fecklessly, jejunely, lemony, melanie, pebbly, pederasty, penally, resiny, selflessly, senselessly, sentiency, stephanie, tepidly, trenchancy, trepidly, vengefully, yemeni, zestily, astheny, el misti, evenki, hellishly, pettishly, sceptically, skeptically, temptingly, threateningly, yenisey

4 syllables:
theosophy, incessantly, technically, rebelliously, transcendency, detestably, acceptably, coquettishly, resplendently, extremity, ascendancy, nonentity, mastectomy, refreshingly, expectancy, identity, expressively, necessity, dependably, lamentably, successfully, inequity, discrepancy, sequentially, obscenity, unsteadily, defensively, lobectomy, ascendency, preferably, deceptively, serenity, fidelity, unpleasantly, nephrectomy, potentially, death penalty, extensively, tremendously, successively, yosemite, devilishly, essentially, desperately, schenectady, lumpectomy, intrepidly, ostensibly, professedly, celebrity, sententiously, complexity, respectively, splenectomy, protectively, authentically, dejectedly, esthetically, insensibly, telemetry, respectfully, collectively, respectably, hegemony, symmetrically, generally, inflexibly, dependency, supremacy, aesthetically, expensively, anemone, domestically, longevity, ethically, repentantly, ineffably, selectively, aggressively, affectingly, hygienically, perplexity, vasectomy, effectively, resplendency, offensively, solemnity, genetically, distressingly, contemptuously, amenity, federally, subjectively, excessively, heredity, perceptibly, convexity, incredibly, integrity, allegedly, indemnity, objectively, incessancy, attentively, collectedly, dementedly, impressively, separately, telepathy, progressively, licentiously, regrettably, thrombectomy, tentatively, infectiously, penelope, acephaly, confessedly, defencelessly, domenici, forelady, illegibly, impendency, impetuously, inclemency, jack kennedy, lieutenancy, neurectomy, perplexedly, polemically, pretentiously, quiescency, refreshfully, relentlessly, revengefully, shell entity, unhelpfully, vulvectomy, with empathy, frenetically, obsessively, suggestively, unendingly, unethically, unselfishly

5 syllables:
tonsillectomy, orchidectomy, geochemistry, mask of pregnancy, comprehensively, pathetically, hysterectomy, apprehensively, eventually, sympathectomy, life expectancy, sentimentally, academically, exceptionally, consequentially, geometrically, ineffectively, confederacy, infidelity, biochemistry, accidentally, mastoidectomy, independently, tubal pregnancy, overwhelmingly, reverentially, oophorectomy, white supremacy, professionally, stapedectomy, orchiectomy, pneumonectomy, salpingectomy, thyroidectomy, condescendingly, disrespectfully, appendectomy, penitentially, irreverently, macrencephaly, abstemiously, rhytidectomy, incidentally, unexpectedly, hypothetically, imperceptibly, intemperately, open sesame, providentially, high fidelity, prostatectomy, unacceptably, deferentially, photochemistry, independency, conscientiously, embolectomy, microcephaly, fundamentally, anencephaly, reprehensibly, unsuccessfully, acrocephaly, change integrity, clinocephaly, coalescency, create mentally, detrimentally, drunken revelry, high-fidelity, hydrocephaly, intumescency, laminectomy, laryngectomy, line of destiny, macrocephaly, megacephaly, meniscectomy, mortal enemy, mountain ebony, nanocephaly, naval weaponry, of necessity, scaphocephaly, school of dentistry, sigmoidectomy, unforgettably, unpretentiously, unrepentantly, act reflexively, anti-semite, asymmetrically, empathetically, inattentively, inexpensively, inexpressively, inoffensively, kinaesthetically, kinesthetically, move reflexively, reprehensively, unimpressively, unrelentingly, unsymmetrically

6 syllables:
cholecystectomy, unconventionally, coincidentally, biogeography, unintentionally, argumentatively, environmentally, radiochemistry, physical chemistry, sympathetically, simple mastectomy, impetuosity, manifest destiny, theoretically, interdependency, electrochemistry, organic chemistry, cercopithecidae, experimentally, cosmetic dentistry, inconsequentially, adrenalectomy, immunochemistry, adenoidectomy, anas penelope, appendicectomy, change of integrity, genus penelope, militant tendency, ovariectomy, panhysterectomy, pedal extremity, unsentimentally, die unexpectedly, noncomprehensively, unenergetically, unsympathetically

7 syllables:
ovarian pregnancy, radical mastectomy, inorganic chemistry, paleogeography, abdominal pregnancy, total hysterectomy, department of chemistry, executive clemency, feeling of identity, john fitzgerald kennedy, suprarenalectomy

8 syllables:
radical hysterectomy, conformational entropy, interpersonal chemistry

10 syllables:
modified radical mastectomy