Dead as a doornail is a phrase which means not alive, unequivocally deceased. The term goes back to the 1300s, the phrase dead as a doornail is found in poems of the time. The term dead as a doornail was used in the 1500s by William Shakespeare, and in Charles Dickens’ A Christmas Carol in 1843. It is thought that the phrase dead as a doornail comes from the manner of securing doornails that were hammered into a door by clenching them. Clenching is the practice of bending over the protruding end of the nail and hammering it into the wood. When a nail has been clenched, it has been dead nailed, and is not easily resurrected to use again. An alternative wording of the phrase dead as a doornail is deader than a doornail.
Remember when everyone associated with Game of Thrones was like, “Jon Snow is dead as a doornail?” (Marie Clair Magazine)
Like old Marley, it was as dead as a doornail. (The Hindu)
Starting their first innings with only 62 overs left in the match, and the contest and their season dead as a doornail, Warwickshire’s batting predictably lacked intensity. (The Nottingham Post)
Efforts to follow Colorado’s lead and legalize recreational marijuana are “dead as a doornail” for California in 2014, after the national Drug Policy Alliance withdrew a proposed initiative that would regulate the drug statewide, says longtime statewide political consultant Steve Maviglio. (LA Weekly)
“No one is on Santa Monica Beach or Zuma Beach. Hardly anyone is on [the] Pacific Coast Highway. It’s dead as a doornail out there,” he said. (The Los Angeles Times)
Alderson was adamant the deal was as dead as a doornail, however. (The New York Post)
Never mind that the badge really reads OPP, that “walrus” isn’t Greek for anything, that most of the story is even less credible, and that the first paragraph inelegantly declared McCartney to be “deader than a doornail.” (The Detroit News)