be on

1. Be taking medication or an illegal drug, as in Are you on some antibiotic? or He was definitely on narcotics when it happened . [1930s]

2. Be in favor of something or willing to participate, as in We're going dancing after the play—are you on? [ Colloquial ; late 1800s]

3. Be engaged in some action, especially on the stage, as in Hurry up, you're on in five minutes . [Late 1700s]

4. Perform extremely well, as in I can't return Dan's serve—he's really on today . [ Slang ; second half of 1900s]

5. Be scheduled, as in Is tonight's rally still on? [ Colloquial ; second half of 1990s]

6. be on one . Be at one's expense, either as a treat or the butt of a joke. For example, This round of drinks is on me , or He enjoys a good laugh, even when the joke's on him . [ Colloquial ; second half of 1800s]

7. not be on . Be unacceptable, not allowable, as in I can't believe you'd cancel; that's just not on . This usage is more common in Britain than America. [ Colloquial ; 1930s] For a synonym, see not done . Also see be on to .

8. see be on.

Related Words

• display 
• execute 
• give 
• go on 
• offer 
• play 
• present 
• produce 
• represent 
• show 
• stage