Iconoclast (n)Person who attacks settled beliefs or institutions
Ex. "An iconoclast can be unpleasant company."Idiosyncrasy (n)Peculiarity of temperament
Ex. "All people have at least one idosyncracy that makes them different from each other."Impervious (adj)Incapable of being harmed or damaged; impenatrable
Ex. "Due to his trauma, the man was impervious to pain."Impetous (adj)Marked by impulsive passion or force and violence of movement or action
Ex. "This impetuous behaviour ultimately led to their deaths."Implausible (adj)Improbable; provoking disbelieves
Ex. "The student gave the teacher an implausible excuse."Impudent (adj)Marked by cocky boldness or disregard for others
Ex. "Cusco was a very impudent emperor."Impugn (v)Attack by words or argument; attack as false or lacking
Ex. "John McCain attempted to impugn Barack Obama's patriotism."Incredulous (adj)Unwilling to accept or admit as true
Ex. "We find it incredulous that defendant had any intent other than the armed robbery."Indigent (adj)Extremely impoverished
Ex. "The man lost his job and became indigent."Indignant (adj)Angry, especially at wrong doing
Ex. "Sally was indignant when the other kids called her fat."Indiscreet (adj)Lack of prudence
Ex. "I thought it was very indiscreet of her to tell her sister's secrets to the whole class."Indolent (adj)Averse to activity, effort or movement
Ex. "Unlike her hardworking brother, she had alot of indolence."Iniquity (n)Wickedness, gross injustice
Ex. "He had to be punished for his iniquity."Innocuous (adj)Harmless; not likely to offend
Ex. " Mary bit eagerly into the innocuous brownie."Inordinate (adj)Exceeding reasonable limits
Ex. " They shut the construction site down due to the inordinate number of worker injuries."Insidious (adj)Harmful but enticing
Ex. "The stalker was insidious in his attempts to reach his victim."Insipid (adj)Lacking qualities that interest, stimulate or challenge; lacking flavor
Ex. " Without hot sauce, the nachos tasted insipid."Insolent (adj)Insultingly arrogant in speech or conduct
Ex. "The insolent young man was rude and disrespectful to everyone he knew."Intimate (v)Communicate delicately and indirectly
Ex. " My sister intimated that she was pregnant."Irreverent (adj)Lacking proper respect or seriousness
Ex. "Talking loudly in church is an irreverent action."