Where does “inexcusably” come from?
inexcusably (English) comes from English inexcusable, from Middle French inexcusable, from Latin inexcusabilis, from Latin excusabilis, from Latin -bilis, from Proto-Italic -ðlis, from Proto-Indo-European -dʰlis, from Proto-Indo-European -dʰlom — Alternative form of *-trom; instrumental suffix;...
inexcusably (English): In an inexcusable manner
Ancestry of “inexcusably”, step by step