Iconoclast
One who attacks popular beliefs or institutions
Ideology
A system of social or political ideas
Idiosyncrasy
An eccentricity
Idyllic
Naturally peaceful
Ignominy
Deep disgrace
Illicit
Illegal
Immigrate
To move permanently to a new country
Imminent
Just about to happen
Immutable
Unchangeable
Impartial
Fair
Impeccable
Flawless
Imperial
Like an emperor or an empire
Impervious
Not allowing anything to pass through
Impetuous
Extremely impatient
Implement
To carry out
Impotent
Powerless
Impugn
To attack
Inane
Silly
Inaugurate
To begin officially
Incandescent
Brilliant
Incantation
A chant
Incense
To make very angry
Incessant
Unceasing
Incipient
Beginning