a. [ L. atrox, atrocis, cruel, fierce: cf. F. atroce. ] 1. Extremely heinous; full of enormous wickedness; as, atrocious guilt or deeds. [ 1913 Webster ]

2. Characterized by, or expressing, great atrocity. [ 1913 Webster ]

Revelations . . . so atrocious that nothing in history approaches them. De Quincey. [ 1913 Webster ]

3. Very grievous or violent; terrible; as, atrocious distempers. [ Obs. ] Cheyne. [ 1913 Webster ]

Syn. -- Atrocious, Flagitious, Flagrant. Flagitious points to an act as grossly wicked and vile; as, a flagitious proposal. Flagrant marks the vivid impression made upon the mind by something strikingly wrong or erroneous; as, a flagrant misrepresentation; a flagrant violation of duty. Atrocious represents the act as springing from a violent and savage spirit. If Lord Chatham, instead of saying “the atrocious crime of being a young man, ” had used either of the other two words, his irony would have lost all its point, in his celebrated reply to Sir Robert Walpole, as reported by Dr. Johnson. [ 1913 Webster ]

-- A*tro"cious*ly, adv. -- A*tro"cious*ness, n. [ 1913 Webster ]

n. 1. the quality of being shockingly cruel and inhumane.
Syn. -- atrocity, barbarity, barbarousness, heinousness. [ WordNet 1.5 ]