INEXCUSABLY
unjustifiably, inexcusably
(adverb) without any excuse; “he is unjustifiably harsh on her”
inexcusably, unpardonably, unforgivably
(adverb) in an unpardonable manner or to an unpardonable degree; “he was inexcusably cruel to his wife”
Source: WordNet® 3.1
Etymology
Adverb
inexcusably (comparative more inexcusably, superlative most inexcusably)
In an inexcusable manner.
Source: Wiktionary
In`ex*cus"a*bly, adv.
Definition: With a degree of guilt or folly beyond excuse or justification.
Inexcusably obstinate and perverse. Jortin.
INEXCUSABLE
In`ex*cus"a*ble, a. Etym: [L. inexcusabilis: cf. F. inexcusable. See
Excuse.]
Definition: Not excusable; not admitting excuse or justification; as,
inexcusable folly.
Therefore thou art inexcusable, O man, whosoever thou art that
judgest; for wherein thou judgest another, thou condemnest thyself;
for thou that judgest doest the same things. Rom. ii. 1.
Source: Webster’s Unabridged Dictionary 1913 Edition