unpardonable

Synonyms:
3. absolution, remission. Pardon, amnesty, reprieve are nouns referring to the cancellation, or delay with the possibility of eventual cancellation, of a punishment or penalty assigned for the violation of a military regulation or a civil law; absolution from guilt is not implied, merely a remission of the penalty. A pardon is granted to an individual, often by the action of a government official such as a governor, president, or monarch, and releases the individual from any punishment due for the infraction of the law, as a death sentence, prison term, or fine: to be released from prison with a full pardon. An amnesty is a pardon granted to a group of persons for past offenses against a government; it often includes an assurance of no future prosecution: to grant amnesty to political prisoners; an amnesty period for delinquent taxpayers during which no penalties are assessed. A reprieve is a delay of impending punishment, especially a death sentence; it does not cancel or remit the punishment, it simply delays it, usually for a specific period of time or until a decision can be arrived at as to the possibility of pardon or reduction of sentence: a last-minute reprieve, allowing the filing of an appeal to the Supreme Court. 6. acquit, clear. See excuse. 7. forgive, absolve, condone, overlook.

Antonyms:
5. censure, blame.