Wiktionary
unforgivably
adv. In an unforgivable manner.
WordNet
unforgivably
adv. in an unpardonable manner or to an unpardonable degree; "he was inexcusably cruel to his wife" [syn: inexcusably, unpardonably] [ant: excusably, excusably, excusably]
Usage examples of "unforgivably".
But is there anything in the offing for you, or have you been unforgivably insolent while standing at the end of a plank, so to speak?