FORTH-forthcoming forthright forthwith

　　HECTO-hectogram hectograph hectoliter hectometer

　　HETERO-heteroclite heterocyclic heterodox heterogeneous heteronym

　　HEXA- hexagon hexagram hexameter hexangular hexapod

　　IN-incriminate inbeing inborn inbreathe incarcerate incarnate incense incentive inceptive incident incipient incise incline include income increase incriminate incubate incur incurve indoor induce indulge infatuate infect infiltrate inflame inflate influence infringe infuriate infuse ingrained inhale inherit inhibit inject injunction inlet innate innovate inquire inroad inscribe insect insert insight inspect inspirit intake intoxicate intricate intrigue intuition inundation inure invade inveigle invest investigate involve illation illuminate illusion illustrate imbibe immanent immerge immigrate impair impale impart impeach impediment impenetrate impersonate impinge implant implement implicate imply import impose impound impoverish imprecate impregnate imprint imprison irradiate irrigate irruption

　　IN-inaccessible inadequate inaudible incautious incomparable inconsistent indecisive indigestion indispensable inequality infallible infamous innutrition invaluable invulnerable enemy ignoble ignominy ignorant illegal illegitimate illiberal illicit illiterate illogical immaculate immature immeasurable immediate immense immodest immortal immutable impalpable imparity impartial impecunious impenetrable impenitent impious implacable impotent imprudent irrational irredeemable irregular irrelative irrelevant irreligious irresistible irresolute irresponsible

　　INTER-intercept interchange interfere interfuse interim interior interjacent interlace interlude intermingle intermit intermix international interplay interpolate interpose interpret interrupt intersect intersperse interstellar interstice intervene intertwine interval interweave enterprise entertain intellect intelligence

　　INTRA-/INTRO- intrapersonal intra-school intravenous introduce introspect introvert

　　ISO-isobar isochronal isogloss isomer isometric isotherm isotope

　　KILO-kilobyte kilocalorie kilocycle kilogram kilohertz kilolitre kilometer kiloton kilovolt kilowatt

　　MACRO- macrobiotics macrocosm macroeconomics macro-engineering macromolecule macroscopic

　　MEGE- megalith megalomania megaphone megaton megavolt megawatt

　　MICRO-microanalysis microbe microbiology microcosm microeconomics micrometeorology microphone microscope microwave

　　MIS-misaddress misadvise misapply misapprehend misarrange misbelieve mischance mischief misconduct misdate misdeed misfortune mislead misogynist misplace mispronounce misstate misstep mistrust misunderstand

　　MULTI- multicolor multifarious multiform multilingual multiply multipurpose multitude

　　NE-nefarious nescience neuter naught nay neither never none null negotiate

　　NEO-neoclassicism neocolonialism neoimpressionism neologism neonatal neophyte NON-nonaggression nonaligned noncombatant noncombustible noncommittal nondurable nonentity nonessential nonmember nonpartisan nonsectarian nonverbal

　　OB-obdurate obedient obfuscate obituary object objurgate oblige oblique oblong obscene obstacle obstinate obstruct obtain obvious omit occasion occult occupy occur offend offer opponent oppress ostentation

　　OCTA-octagon octahedron octave octavo October octopus

　　OMNI-omnibus omnipotent omnipresent omniscient omnivorous

　　OUT- outbreak outdo outgrow outlandish outlaw outline outlive outnumber outpace outrage outrival outrun outwear outwit

　　OVER-overact overbear overburden overcast overcoat overcome overcrowd overdo overeat overestimate overflow overhang overhaul overhear overlap overlay overload overlook overnight overpay overpower overrate overseas overset oversight oversleep overtake overthrow overturn overwhelm

　　PEN-peninsula penultimate penumbra