Inexorable
Cannot be moved or influenced by persuasion or entreaty. Adj
Inert
Having no power to act or move, inactive. Adj
Inscrutable
Cannot be easily understood, mysterious. Adj
Intrepid
With out fear, brave. Adj
Irascible
Easily angered. Adj
Jaundiced
Prejudiced. Adj
Jingoism
Extreme patriotism, favoring an aggressive warlike foreign policy. Noun
Jocose
Joking, humorous. Adj
Juggernaut
A terrible destructive or irresistible force. Noun
Lethargy
Lack of energy, drowsiness, disinterest. Noun