red herring
Red herring (noun) means something introduced into an argument, investigation or story that draws attention away from the real issue, whether by accident or on purpose. Example: “The missing key turned out to be a red herring; the door was never locked.”
How to use red herring
Learner’s notesIn plain EnglishSomething that pulls your attention away from what actually matters.
Neutral; common in journalism, fiction criticism and debate.
Fill the gap
Can you complete this real example?
The missing key turned out to be a _____; the door was never locked.
Etymology
From the strong-smelling cured fish of the third sense. The often-repeated story that such fish were dragged across trails to train or mislead hounds is disputed, and the exact route to the figurative meaning is not settled.