Inexcusable, a.
Etymology: [L. inexcusabilis: cf. F. inexcusable. See Excuse.]
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.
Shades of meaning
Fernald lists inexcusable only as an antonym, under venial.
He lists it without comment; the entries above explain its neighbors.
Synonyms
none given