inexcusably

adverb

1. in an unpardonable manner or to an unpardonable degree

   adv.all

   Examples

   He was inexcusably cruel to his wife.

   Synonyms unforgivably unpardonably

   Antonyms excusably forgivably pardonably

   Source: WordNet 3.0

2. without any excuse

   adv.all

   Synonyms unjustifiably

   Antonyms justifiably

   Source: WordNet 3.0

3. With a degree of guilt or folly beyond excuse or justification.

   adverb

   Source: webster1913