Police are investigating a vicious attack that left an elderly man hospitalized.

vicious 源自拉丁语 vitiosus,词根 viti- 来自 vitium(过错、缺陷),加上形容词后缀 -ous(充满……的),原义为"充满恶习的、有缺陷的",引申为"凶残的、恶毒的"。这里形容袭击者的手段极其凶残恶劣。