The phrase "deadly weapon" refers to any object that can be used to cause serious harm or death. This term is often used in legal contexts to describe items that have been used in crimes or acts of violence. Some common synonyms for deadly weapon include lethal weapon, dangerous weapon, deadly instrument, and lethal instrument. Other synonyms may include tools or devices that are specifically designed for use in combat or self-defense, such as knives, guns, bombs, and other explosives. While these items may have legitimate purposes, their potential to cause harm makes them dangerous and potentially deadly in the wrong hands.