irascible, irate, iridescent, irk, irksome, ironic, irony, irrational, irreconcilable, irrecoverable, irreducible, irrefutable, irregular, irregularity, irrelevant, irreparable, irreproachable, irresistible, irresolute, irresponsible, irreverent, irrevocable, irrigation, irritate, irritating, irritation