3 syllables:
thetically

4 syllables:
aesthetically, aphetically, ascetically, athletically, auxetically, balletically, bathetically, cosmetically, eidetically, emetically, esthetically, frenetically, gametically, genetically, hermetically, kinetically, luetically, magnetically, mimetically, pathetically, phonetically, phrenetically, phyletically, poetically, prophetically, prosthetically, prothetically, syndetically, synthetically

5 syllables:
alphabetically, anesthetically, antithetically, apathetically, arithmetically, asyndetically, catechetically, cybernetically, dietetically, diuretically, empathetically, energetically, exegetically, geodetically, homiletically, hypothetically, inergetically, kinaesthetically, kinesthetically, metathetically, parenthetically, quodlibetically, sympathetically, theoretically

6 syllables:
antipathetically, apologetically, autogenetically, biogenetically, biosynthetically, chemosynthetically, cladogenetically, cytogenetically, diagenetically, diamagnetically, epexegetically, epigenetically, geomagnetically, logarithmetically, morphogenetically, ontogenetically, orthogenetically, palingenetically, peripatetically, photosynthetically, phylogenetically, polyphyletically, telekinetically, unenergetically, unsympathetically

7 syllables:
abiogenetically, electromagnetically, parasympathetically, parthenogenetically, psychotomimetically, unapologetically

8 syllables:
onomatopoetically

2 syllables:
thessaly

3 syllables:
severally, splendidly, pleasantly, messily, tendency, ebony, pedigree, credibly, gemini, venally, leprosy, prelacy, lengthily, elegy, readily, tenantry, weaponry, helplessly, equity, zestfully, remedy, breathlessly, brevity, revelry, flexibly, melody, steadily, entity, jealousy, restfully, enemy, seventy, entropy, tensity, peasantry, clemency, velvety, threnody, sensibly, devilry, chemistry, pedantry, pregnancy, legacy, bestially, cecity, necropsy, sesame, zealotry, mentally, density, dreadfully, helpfully, testily, specially, embassy, tenancy, pleasantry, centrally, kennedy, deputy, secondly, enmity, legatee, felony, preciously, recipe, ecstasy, especially, debauchee, specialty, presently, destiny, heavily, heavenly, medically, endlessly, empathy, jealously, chemically, penalty, astheny, dentistry, devilishly, effigy, el misti, emily, ethically, ethnically, evenki, hellishly, helsinki, jestingly, levity, negligee, pettishly, registry, sceptically, selfishly, skeptically, technically, temptingly, threateningly, yenisey

4 syllables:
theosophy, incessantly, rebelliously, transcendency, detestably, acceptably, resplendently, extremity, ascendancy, nonentity, mastectomy, expectancy, identity, necessity, dependably, lamentably, successfully, inequity, discrepancy, sequentially, unsteadily, lobectomy, ascendency, preferably, serenity, fidelity, unpleasantly, nephrectomy, potentially, death penalty, tremendously, essentially, flux density, desperately, schenectady, lumpectomy, intrepidly, ostensibly, sententiously, complexity, splenectomy, insensibly, telemetry, respectfully, respectably, hegemony, generally, inflexibly, dependency, supremacy, anemone, longevity, repentantly, ineffably, perplexity, vasectomy, resplendency, solemnity, contemptuously, amenity, federally, intensity, heredity, perceptibly, convexity, incredibly, integrity, allegedly, indemnity, incessancy, separately, telepathy, licentiously, low density, regrettably, thrombectomy, tentatively, infectiously, penelope, affectingly, aggressively, attentively, authentically, celebrity, collectedly, collectively, coquettishly, deceptively, defensively, dejectedly, dementedly, distressingly, domestically, effectively, excessively, expensively, expressively, extensively, impressively, objectively, obscenity, obsessively, offensively, progressively, propensity, protectively, refreshingly, respectively, selectively, subjectively, successively, suggestively, symmetrically, unendingly, unethically, unselfishly, yosemite

5 syllables:
tonsillectomy, orchidectomy, geochemistry, mask of pregnancy, hysterectomy, eventually, sympathectomy, life expectancy, sentimentally, exceptionally, consequentially, confederacy, biochemistry, accidentally, mastoidectomy, independently, tubal pregnancy, reverentially, oophorectomy, white supremacy, professionally, stapedectomy, orchiectomy, pneumonectomy, salpingectomy, thyroidectomy, disrespectfully, appendectomy, penitentially, irreverently, macrencephaly, abstemiously, rhytidectomy, incidentally, intemperately, open sesame, providentially, high fidelity, prostatectomy, unacceptably, deferentially, photochemistry, independency, conscientiously, embolectomy, microcephaly, fundamentally, vapor density, anencephaly, reprehensibly, unsuccessfully, academically, act reflexively, anti-semite, apprehensively, asymmetrically, comprehensively, condescendingly, geometrically, imperceptibly, inattentively, ineffectively, inexpensively, inexpressively, infidelity, inoffensively, move reflexively, overwhelmingly, reprehensively, unexpectedly, unimpressively, unrelentingly, unsymmetrically

6 syllables:
cholecystectomy, unconventionally, coincidentally, biogeography, unintentionally, environmentally, radiochemistry, physical chemistry, simple mastectomy, impetuosity, manifest destiny, interdependency, electrochemistry, organic chemistry, cercopithecidae, experimentally, cosmetic dentistry, inconsequentially, adrenalectomy, immunochemistry, relative density, die unexpectedly, noncomprehensively

7 syllables:
ovarian pregnancy, radical mastectomy, inorganic chemistry, magnetic flux density, paleogeography, abdominal pregnancy, total hysterectomy

8 syllables:
radical hysterectomy

10 syllables:
modified radical mastectomy