not on

Definition of not on

British, informal
1 :not acceptable or proper
  • Cheating old ladies out of their savings just isn't on.
2 :not possible
  • I'm afraid that scheme's just not on.

Seen and Heard

What made you want to look up not on? Please tell us where you read or heard it (including the quote, if possible).

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

serious difficulty or misfortune

Get Word of the Day daily email!

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!