Toothpaste promise 

Noun. A representation made, usually in advertising, that sounds impressive, but is effectively meaningless.
Based on the claim that all toothpaste ads make, i.e. 70% more effective (than brushing without toothpaste).

They said I could save hundreds of dollars per year on my car insurance, but that was compared to someone who never shops around, and has had the same policy for 10 years. It's always cheaper to switch to any other insurance company after a couple of years, so it was a total toothpaste promise.

Toothpaste promise by Werdenschmidt February 7, 2021