Something used to divert attention form the real matter, issue or object(a dead red herring was often used to confuse or test the scent of a hunting dog)

(noun) A person who sits on the front porch and intimidates, says negative things, or otherwise makes things unpleasant for those nearby.

In novels, usually mystery novels, a "red herring" is an extraneous character meant to divert the reader's attention from the true killer/robber/etc. It is usually a logical choice for the culprit, but ends up being nothing.

Red herrings were often used by jail birds to mislead hound dogs that were tracking them.

The expression "red herring" refers to something that is misleading.

Herrings put into a tub with salt or brine, later spitted on sharp wooden spits, and hung up in a chimney to be smoked and dried. Such preserved fish would keep for months (and indeed they were transported in barrels to provide protein on long sea voyages) but were inedible in this state and needed to be soaked to soften them and remove the salt before they could be cooked.

Do I smell a rat?

One key characteristic of red herrings, apart from their colour, was their strong smell, so much so that one use for them on occasion was to train hounds to follow a scent.

a deliberately misleading object

technique used by politicians, often conservatives, to distract voters' attention away from real and true issues that need immediate address.

a passe term that most folks would like to dispense with - bringing to mind smelly fish. A pretentious saying that only pundits and a-holes use.