3 syllables:
sneakily, decency, equally, peacefully, leniently, genially, legally, greedily, chieftaincy, threepenny, vis-a-vis, regency, secrecy, speedily, peaceably, evilly, dreamily, penally, recently, decently, easily, leniency, frequency, gleefully, ceaselessly, lemony, evenly, frequently, audibly, balmily, blossomy, bodily, bonduc tree, bonhomie, botany, bottletree, broccoli, caudally, colloquy, colony, comedy, commonly, comparably, conakry, connally, consciously, constancy, constantly, cosily, cozily, crotchety, dottily, foxily, gossipy, guenon monkey, homily, honestly, honesty, hostelry, hostilely, knobbly, modestly, modesty, monody, monstrously, novelty, noxiously, obloquy, oddity, odyssey, policy, polity, possibly, probably, prodigy, progeny, promisee, prophecy, prophesy, prosody, psalmody, ptolemy, quality, quantity, rocketry, romany, rommany, rottenly, sodomy, solidly, sovereignty, squalidly, stodgily, talkily, wallaby, wannabe, wannabee, wantonly, watchfully, wobbly

4 syllables:
unequally, deceitfully, unevenly, obesity, high frequency, indecency, infrequently, conveniently, facetiously, vehemently, obscenely, treacherously, low frequency, infrequency, conceivably, unspeakably, illegally, relevantly, uneasily, agronomy, algometry, allometry, allotropy, androgeny, anomaly, apogamy, apostrophe, arthrography, arthroscopy, astrolatry, astrometry, astronomy, atrocity, autocracy, autogeny, autonomy, bardolatry, biogeny, biography, bureaucracy, cacography, cacophony, calabash tree, callosity, cartography, child prodigy, commodity, cosmography, cosmolatry, democracy, demography, demonstrably, despondency, despondently, dichotomy, dishonesty, economy, equality, ethnography, exogamy, farce comedy, ferocity, fluoroscopy, frivolity, gastronomy, geodesy, geography, geometry, globosity, glyptography, gymnosophy, high quality, homogeny, hydrography, hydrometry, hypocrisy, idolatry, immodestly, immodesty, impossibly, improbably, inconstancy, insolvency, isogamy, isometry, lithography, lithotomy, lordolatry, low comedy, low quality, mahogany, mammography, monocracy, monogamy, monopoly, monopsony, monotony, monstrosity, naprapathy, obnoxiously, old colony, ontogeny, optometry, orthography, philosophy, phonology, photography, phylogeny, planography, plutocracy, pornography, porosity, precocity, prime quantity, psychometry, pyrolatry, responsibly, self-consciously, shape constancy, size constancy, sonography, spectrometry, spectroscopy, symbolatry, tax policy, theocracy, theosophy, thermometry, top-quality, topography, topolatry, trade policy, tuatha de, typography, unconsciously, velocity, venography, verbolatry, verbosity, viscometry, viscosity, with modesty, zoolatry

5 syllables:
obediently, unbelievably, anemography, anemometry, animosity, anorthography, anthropolatry, anthropometry, arborolatry, aristocracy, audiometry, bibliography, bibliolatry, brightness constancy, cardiography, celioscopy, choreography, chromatography, color constancy, complex quantity, constant quantity, crystallography, curiosity, defence policy, defense policy, demonolatry, densitometry, diabolatry, disconsolately, fiscal policy, floating policy, foreign policy, generosity, glutinosity, grandiosity, gynaeolatry, gyneolatry, hagiography, hagiolatry, heliolatry, iconolatry, ideography, idiolatry, inequality, irresponsibly, laparoscopy, laparotomy, lexicography, mass spectroscopy, mediocrity, news photography, numerosity, oceanography, paleography, passamaquody, physiography, plane geometry, preciosity, radiography, radioscopy, roentgenography, social policy, sociometry, symbololatry, thaumatolatry, tragicomedy, trigonometry, true anomaly, true mahogany, tuberosity, unknown quantity, unselfconsciously, without modesty, xerography

6 syllables:
cardiomegaly, very high frequency, ovariectomy, very low frequency, relative frequency, audio frequency, medium frequency, radio frequency, antimonopoly, arteriography, autobiography, biogeography, cedar mahogany, cholangiography, cholelithotomy, chromolithography, cinematography, cuban mahogany, decline in quality, definite quantity, escape velocity, hypervelocity, insurance policy, legal philosophy, mammothermography, managed economy, market economy, maternal quality, moral philosophy, musical comedy, muzzle velocity, offset lithography, palaeobotany, paleobotany, parental quality, paternal quality, photolithography, powder photography, relative quantity, religiosity, seriocomedy, social democracy, solid geometry, telephotography, token economy, ultrasonography, voluminosity

7 syllables:
extremely low frequency, fundamental frequency, extremely high frequency, absolute viscosity, african mahogany, column chromatography, communist economy, descriptive geometry, dialect geography, doctor of optometry, doctor of philosophy, dynamic viscosity, economic policy, electromyography, honduras mahogany, indefinite quantity, linguistic geography, natural philosophy, numerical quantity, palaeoethnography, palaeogeography, paleoethnography, paleogeography, paper chromatography, parametric quantity, philippine mahogany, physical geography, projective geometry, radio astronomy, situation comedy, socialist economy, spherical geometry, terminal velocity, unit of viscosity, variable quantity

8 syllables:
analytic geometry, capitalist economy, congenital anomaly, coordinate geometry, department of philosophy, dominican mahogany, economic geography, elementary geometry, empiricist philosophy, hyperbolic geometry, large indefinite quantity, national trading policy, parabolic geometry, political economy, proprietary colony, small indefinite quantity, transcendental philosophy

9 syllables:
african scented mahogany, analytical geometry, coefficient of viscosity, parliamentary democracy

11 syllables:
council on environmental policy