inexcusable
/ˌɪnɪkˈskjuzəbəl/
adjective
- Too bad or wrong to be forgiven or justified; not acceptable.
- The company's failure to fix the safety problem was inexcusable.
- His rude behavior toward the waiter was inexcusable.
- Forgetting your best friend's birthday is not just a mistake—it's inexcusable.
Antonyms