4 syllables:
geogony

3 syllables:
wallaby, colony, comradely, hostilely, broccoli, modesty, wannabe, possibly, rocketry, ology, quantity, novelty, policy, bodily, sodomy, botany, psalmody, homily, prodigy, sovereignty, monstrously, boloney, honesty, twopenny, audibly, frostily, honestly, constantly, quality, ptolemy, hostelry, bonhomie, comedy, dobsonfly, solidly, dovekie, commonly, potbelly, potently, romany, polony, constancy, monody, progeny, wantonly, modestly, consciously, gossipy, colloquy, crotchety, prosody, monandry, cobwebby, odyssey, prophecy, contrasty, probably, wobbly, wannabee, polity, oddity, conakry

4 syllables:
monopsony, ontogeny, monotony, volubly, autonomy, pomology, cacophony, synonymy, astronomy, psephology, verbosity, technology, sinology, topography, horology, colostomy, conchology, mycology, misogamy, aerology, oncology, demography, geometry, zoology, homogeny, economy, monopoly, ecology, frivolity, garbology, doxology, tocology, neurology, philology, democracy, apostrophe, cytology, lithography, ontology, impolitely, anthology, pornography, comradery, thermometry, geology, geodesy, phonology, phytology, hypocrisy, nosology, demonstrably, orthography, ethnology, penology, gastronomy, atrocity, loquacity, velocity, misology, typography, ichthyology, agrology, trade policy, improbably, viscosity, impossibly, apostasy, moronity, comparably, proctology, equality, commodity, despondently, inconstancy, porosity, spectroscopy, gibbosity, prodigally, impotency, pathology, philosophy, bureaucracy, planography, dishonesty, photography, theology, neology, virology, conjugally, apology, cartography, monstrosity, jocosity, unconsciously, ethology, serology, psychology, mammography, ethnography, insolvency, allopathy, hydrometry, theocracy, phylogeny, tautology, optometry, morphology, agronomy, otology, astrometry, callosity, urology, histology, ferocity, hydrology, geography, mythology, despondency, chronology, posology, anomaly, biology, responsibly, allometry, biography, dichotomy, fluoroscopy, phrenology, low comedy, holography, astrology, enology, idolatry, spectrometry, homology, monogamy, seismology, autocracy, precocity, petrology, limnology

5 syllables:
sinuosity, laparoscopy, hematology, macrocephaly, archeology, anemometry, toxicology, aetiology, cardiography, angiology, actinometry, physiology, eschatology, teratology, rheumatology, anthropology, etymology, child psychology, uranology, true anomaly, dermatology, hagiology, volcanology, mineralogy, bibliography, depth psychology, audiometry, lexicography, haematology, ophthalmology, radiology, axiology, fiscal policy, primatology, inequality, scientology, embryology, adiposity, herpetology, gynaecology, parisology, roentgenography, stereoscopy, tortuosity, etiology, high technology, jejunostomy, crystallography, aristocracy, foreign policy, ideology, tuberosity, egyptology, trigonometry, oenology, mediocrity, teleology, choreography, radiography, methodology, paleology, speleology, ideography, generosity, terminology, audiology, genealogy, cardiology, archaeology, sociology, poenology, animosity, entomology, immunology, criminology, curiosity, ornithology, climatology, adenopathy, irresponsibly, oceanography, anemography, hagiography, tracheostomy, lexicology, meniscectomy, sociometry, pharmacology, plane geometry, gerontology, numerosity, anthropometry, grandiosity, densitometry, anisogamy, gynecology, chromatography, anorthography, angiography, episiotomy

6 syllables:
neuroanatomy, cardiomyopathy, antimonopoly, token economy, psychopathology, market economy, bacteriology, solid geometry, social democracy, autobiography, social psychology, musical comedy, endocrinology, human ecology, chromolithography, paleobotany, ultrasonography, escape velocity, religiosity, geomorphology, folk etymology, neuropsychology, meteorology, biotechnology, cinematography, parapsychology, glottochronology, offset lithography, palaeontology, epistemology, arteriography, neurobiology, insurance policy, paleontology, numismatology, applied psychology, telephotography, microbiology, moral philosophy, muzzle velocity

7 syllables:
projective geometry, natural theology, situation comedy, anesthesiology, psychopharmacology, physical geography, radio astronomy, clinical psychology, paper chromatography, terminal velocity, spherical geometry, paleopathology, epidemiology, bioclimatology, cognitive psychology, paleobiology, dynamic viscosity, social anthropology, psychophysiology, dialect geography, electromyography, column chromatography, paleornithology, natural philosophy, neurophysiology, doctor of philosophy, immunopathology

8 syllables:
cultural anthropology, micropaleontology, congenital anomaly, physical anthropology, comparative psychology, economic geography, paleoclimatology, molecular biology, proprietary colony, hyperbolic geometry, industrial psychology, paleoanthropology, analytic geometry, political economy

9 syllables:
coefficient of viscosity, developmental psychology, experimental psychology

10 syllables:
physiological psychology