Tell on Definition 1 of 3Pro Tip 1/3Snitching Connotation Carries a negative connotation of betrayal, especially among children. He worried they would tell on him for breaking the window. Pro Tip 2/3Childish Usage More common among children; adults may use it to sound playful or condescending. I can't believe you're going to tell on me—I'm not a child! Pro Tip 3/3Colloquial Context Primarily used in informal situations and spoken language. You're such a tattletale, always ready to tell on your friends.