The word "劈头盖脸" is formed by combining two verb-object phrases in parallel: "劈头" meaning "to strike the head" and "盖脸" meaning "to cover the face", where 劈 denotes striking, 头 is head, 盖 means covering, and 脸 is face; together they literally depict an action aimed at the head and face, thus conveying the sense of a direct and overwhelming assault.