unforgivable

unforgivable /ˌʌnfɚˈgɪvəbəl/ adjective
unforgivable
/ˌʌnfɚˈgɪvəbəl/
adjective
Britannica Dictionary definition of UNFORGIVABLE
[more unforgivable; most unforgivable]
: so bad that it can never be forgiven

— unforgivably

/ˌʌnfɚˈgɪvəbli/ adverb