English Synonym Words Starting With I identical alike, duplicate idle inactive, lazy ignorant uninformed, unaware immaculate spotless, pure immature childish, inexperienced immune resistant, exempt impartial neutral, unbiased, fair impatient eager, anxious, intolerant imperative compulsory, crucial, mandatory imperfect marred, defective, faulty impetuous impulsive, rash, reckless important significant, meaningful independent self-reliant, autonomous inferior lesser, substandard infuriate enrage, agitate, provoke ingenious clever, creative, original innocent guiltless, blameless insane crazy, deranged, mad insufficient inadequate, deficient intelligent bright, sensible, rational interesting provocative, engrossing intermittent sporadic, periodic internal inner, inside intolerant bigoted, prejudiced intriguing fascinating, enthralling irrelevant inappropriate, unrelated irritate annoy, agitate, provoke