The word "心狠手辣" is formed by combining two parallel phrases: "心狠" meaning "cruel heart" and "手辣" meaning "vicious hand". The character 心 (heart) represents inner intent, 狠 (cruel) describes that intent, 手 (hand) represents outward actions, and 辣 (vicious) describes those actions, together denoting a person who is internally malicious and externally brutal.