UNRECONCI'LABLE, 1. That cannot be reconciled; that cannot be made consistent with; as two unreconcilable propositions. [In this sense, irreconcilable is generally used.] 2. Not reconcilable; not capable of being appeased; implacable. 3. That cannot be persuaded to lay aside enmity or opposition, and to become friendly or favorable; as unreconcilable neighbors. [Irreconcilable is generally used.]
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI