What are you, etc. on? Definition 1 of 3Pro Tip 1/3Drug Inference Used when someone's behavior suggests they may be influenced by drugs. He's laughing at nothing. What are you on? Pro Tip 2/3Caution Required Sometimes a sensitive question, implying drug use. Use with people you know well. You're so hyper today. What are you on, buddy? Pro Tip 3/3Joking Tone Often said in a joking or playful manner among friends. You just solved that in seconds. What are you on, a genius pill?