inexpiable
adjective
[ ɪnˈɛkspɪəb(ə)l ]
• (of an offence or feeling) so bad as to be impossible to expiate.
• "an inexpiable sin"
Origin:
late Middle English: from Latin inexpiabilis, from in- ‘not’ + expiabilis ‘able to be appeased’ (from expiare ‘expiate’).
