A false, contrived, or assumed purpose or reason; a pretense.
To employ a pretext, which involves using a false or contrived purpose for soliciting the gain of something else.
A clue, information, argument etc. that is or is intended to be misleading, diverting attention from the real answer or issue.
A herring that is cured in smoke and brine strong enough to turn the flesh red; a type of kipper.
A red herring prospectus.