Definition of deadly

• a. - Capable of causing death; mortal; fatal; destructive; certain or likely to cause death; as, a deadly blow or wound.
• a. - Aiming or willing to destroy; implacable; desperately hostile; flagitious; as, deadly enemies.
• a. - Subject to death; mortal.
• adv. - In a manner resembling, or as if produced by, death.
• adv. - In a manner to occasion death; mortally.
• adv. - In an implacable manner; destructively.
• adv. - Extremely.