unjustifiable
🇺🇸
/ˌʌnˌdʒʌstɪˈfaɪəbl/
🇬🇧
/ˌʌnˌdʒʌstɪˈfaɪəbl/
not able to be defended or explained as reasonable
The company's decision to fire the employee without notice was unjustifiable.