Etymology Borrowed from Middle French irréconciliable, from Late Latin irreconciliābilis, from in- (“not”) + reconciliō (“to reconcile”) + -ābilis (“-able”). By surface analysis, ir- + reconcilable.
1
Unable to be reconciled; opposed; uncompromising.
[T]he fact that the peccant doctor [Sir James Clark, 1st Baronet] continued in the Queen's service made the Hastings family irreconcilable and produced an unpleasant impression of unrepentant error upon the public mind.1921, Lytton Strachey, “Lord Melbourne”, in Queen Victoria, London: Chatto & Windus, →OCLC, section VI, page 82:
2
Incompatible, discrepant, contradictory.
I amused myself by thinking that in his choice of books he showed pleasantly the irreconcilable sides of his fantastic nature.1919, W[illiam] Somerset Maugham, chapter XXVI, in The Moon and Sixpence, [New York, N.Y.]: Grosset & Dunlap Publishers […], →OCLC:
Etymology Borrowed from Middle French irréconciliable, from Late Latin irreconciliābilis, from in- (“not”) + reconciliō (“to reconcile”) + -ābilis (“-able”). By surface analysis, ir- + reconcilable.
1
Something that cannot be reconciled.
Irreconcilable
noun
1
US, Dated, Slang A Confederate who moved to another country following the American Civil War, rather than live in a reunited United States.
2
US, Dated, Slang A vociferous opponent of the Treaty of Versailles.