* Irrelevant: Not relevant or important.
* Irresponsible: Not responsible or accountable.
* Irregular: Not regular or consistent.
* Irreversible: Not capable of being reversed or changed.
* Irreplaceable: Not capable of being replaced.
* Irrational: Not rational or logical.
* Irreconcilable: Not able to be reconciled or resolved.
* Irresistible: Not able to be resisted.
* Irrevocable: Not able to be revoked or cancelled.
* Irrefutable: Not able to be refuted or disproven.
* Irrelevant: Not relevant or important.
* Irreligious: Not religious.
* Irresolute: Not determined or resolute.
* Irrespective: Not dependent on or influenced by.
* Irrespective: Not taking account of or influenced by.
This is not an exhaustive list, but it provides a good starting point.