5 syllables:
anurognathus

2 syllables:
maleness

3 syllables:
abidance, anthesis, adamance, agamous, camelus, fatuous, tantalus, scandalous, anoestrus, fractiousness, antabuse, ravenous, passionless, thalamus, astacus, flatulence, crapulous, handleless, calculus, ampleness, annulus, ambulance, abacus, averageness, tactlessness, acinous, bashfulness, hatefulness, balanus, thankfulness, blasphemous, fabulous, assonance, cannabis, gratefulness, accidents, accidence, abstinence, acanthus, handedness, fathomless, sanguineness, caducous, callousness, randomness, platanus, class-conscious, angelus, handsomeness, ancestress, crapulence, bottomless, cognizance, columnists, commonness, communists, confidence, conscienceless, consciousness, consequence, consonance, continence, continents, documents, dominance, godlessness, honestness, modestness, monuments, noxiousness, obstinance, occupants, oculus, ominous, omnibus, omphalus, onymous, opulence, oxalis, pompousness, populace, populous, populus, profitless, prominence, prophetess, protestants, provenance, providence, romulus, rottenness, scolytus, slothfulness, somnolence, spotlessness, squalidness, stolidness, strophanthus, vomitus, watchfulness

4 syllables:
analysis, unanimous, miraculous, magnanimous, ambassadress, gelatinous, paralysis, iapetus, savageness, astragalus, recalcitrance, anachronous, dialysis, extravagance, capacitance, affableness, analogous, calamitous, intransigence, manageress, ungratefulness, substantialness, incandescence, abdominous, acrogenous, acromphalus, acropolis, ammotragus, androgenous, anonymous, anthophagous, apogamous, apophasis, astomatous, autogenous, autologous, autolysis, autonomous, carpophagous, cryptogamous, cytolysis, endogamous, eponymous, esophagus, exogamous, gymnopilus, hippotragus, homologous, hydrolysis, hypothesis, idolatress, improvidence, incompetence, incontinence, lose consciousness, melophagus, metropolis, monogamous, monotonous, necropolis, nitrogenous, obnoxiousness, oesophagus, panonychus, pathologists, phytophagous, predominance, psychologists, recognizance, reconnaissance, saprophagous, sarcolemnous, sarcophagus, self-confidence, self-consciousness, subconsciousness, synonymous, taurotragus, uncommonness, uropsilus, with confidence, zoophagous

5 syllables:
pusillanimous, oleaginous, cartilaginous, renal calculus, cost analysis, acantholysis, air reconnaissance, amylolysis, anisogamous, anthropophagus, campylotropous, creeping oxalis, disconsolateness, electrolysis, entomophilous, fibrinolysis, genus oxalis, haematolysis, hematolysis, heterologous, hippopotamus, loss of consciousness, megalopolis, nonautonomous, nonnitrogenous, ophiophagus, proteolysis, semiconsciousness, stephanopoulos, stream of consciousness, unselfconsciousness, vote of confidence

6 syllables:
systems analysis, integral calculus, psychoanalysis, flaccid paralysis, predicate calculus, functional calculus, hemodialysis, adrianopolis, bacteriolysis, bacteriophagous, megalobatrachus

7 syllables:
infantile paralysis, harmonic analysis, regression analysis, urinary calculus, differential calculus, displaying incompetence, genus hippopotamus

8 syllables:
qualitative analysis, gravimetric analysis, quantitative analysis, alcoholics anonymous, electronic reconnaissance, urinary incontinence

9 syllables:
infinitesimal calculus

15 syllables:
international society for krishna consciousness