Noun - A joke that is completely unfunny and beyond cheesy. A joke that will stop any points of laughter in a group and cause the person who said the joke to face ridicule. Whenever someone makes a terrible joke you call them out by saying "tampoff"
Verb - calling someone out on a bad joke (to tampoff someone)
The original tampoff: Person 1: "We couldn't have sex because she had her tampon in" Person 2: "Tampon?? Don't you mean, tampoff?"
Example of it in use.
Person 1: Did you know they created health care for alligators? It's called Gator-Aid. (gatorade)
Person 2: Dude, tampoff!