Possible Definitions:
1. Deadly (a.) Capable of causing death; mortal; fatal; destructive; certain or likely to cause death; as, a deadly blow or wound.
2. Deadly (a.) Aiming or willing to destroy; implacable; desperately hostile; flagitious; as, deadly enemies.
3. Deadly (a.) Subject to death; mortal.
4. Deadly (adv.) In a manner resembling, or as if produced by, death.
5. Deadly (adv.) In a manner to occasion death; mortally.
6. Deadly (adv.) In an implacable manner; destructively.
7. Deadly (adv.) Extremely.