A herring that is cured in smoke and brine strong enough to turn the flesh red; a type of kipper.

plural of red herring

(finance) A document that must be submitted by the issuing company as part of a public offering of securities (either stocks or bonds). It is issued to potential investors, but does not have complete particulars on the price of the securities offered or quantum of securities to be issued.

(idiomatic, quasi-adjective) Unsuitable for anyone or anything; unfit for any purpose.