INSANITY—madness, mental aberration, lunacy, delirium. (Sanity.)
INSINUATE—hint, intimate, suggest, infuse, introduce, ingratiate.
INSIPID—dull, flat, mawkish, tasteless, inanimate, vapid, lifeless. (Bright, sparkling.)
INSOLENT—rude, saucy, impertinent, abusive, pert, scurrilous, opprobrious, insulting, offensive.
INSPIRE—animate, exhilarate, enliven, breathe, cheer, inhale.
INSTABILITY—mutability, fickleness, mutableness, wavering. (Stability, firmness.)
INSTIGATE—stir up, persuade, animate, stimulate, incite, urge, encourage.
INSTIL—implant, inculcate, infuse, insinuate.
INSTRUCT—inform, teach, educate, enlighten.
INSTRUMENTAL—conducive, assistant, helping.