| Noun | 1. | autoinjector - a hypodermic syringe to use in injecting yourself with a liquid; "United States troops now carry atropine and autoinjectors in their first-aid kits to use in case of organophosphate nerve agent poisoning"hypodermic, hypodermic syringe, hypo - a piston syringe that is fitted with a hypodermic needle for giving injections |