incapable of being brought into harmony or adjustment; incompatible

irreconcilable differences.

incapable of being made to acquiesce or compromise; implacably opposed

irreconcilable enemies.

a person or thing that is irreconcilable.

a person who is opposed to agreement or compromise.

adjective

compromising , friendly , reconcilable

adjective

clashing , diametrically opposed , discordant , discrepant , dissonant , hard-line , implacable , incompatible , incongruous , inconsistent , inexorable , inflexible , inharmonious , intransigent , opposed , reluctant , unappeasable , uncompromising , unfriendly , conflicting