Dead as a doornail

[ltfire]

Means what, exactly? My mother used this term today, and explained that it meant REALLY dead…LOL…but said she had been using the expression all her life and she is 89. So, whats a doornail and why would it be dead?

[peepthis]

The Word Detective chimes in:

“Dead as a doornail,” meaning utterly, completely dead, first appeared in English way back around 1350 A.D. Shakespeare was quite fond of the phrase and used it in several of his plays, probably for the same reason we still use it today: the alliteration of “dead” and “doornail.” Of the alternatives listed by the Oxford English Dictionary (“dead as a herring” and “dead as mutton”), only “dead as the dodo” packs quite the same poetic punch.

As to why a “doornail,” opinions vary a bit. One theory holds that the “doornail” in question was not a nail as we know nails today, but rather a broad, flat plate mounted on the outside of the door to serve as a striking plate for the door knocker. Such a “nail” would be “dead” because it would be fixed tightly to the wood of the door and thus would not ring when struck as metal normally does, but rather give a dull “thump.” This theory is, in the opinion of most authorities, unlikely to be true.

Probably the best theory about “doornail” notes that until the nineteenth century metal nails were both expensive and rarely used, wooden pegs being the norm. Metal nails were used in the construction of doors, however, usually driven clear through the door and then bent over on the other side, rendering them immovable. Such nails were called “dead” in the jargon of carpentry at the time because they could not loosen and work themselves free. “Dead as a doornail” is thus not just a very old saying, but a very old pun as well.

[Forbin]

I don’t know if this is the “authentic” answer, but here goes.

If you were to construct a Z-batten door in the traditional fashion, you would employ nails in the following manner.
1-drive a nail fastening the batten (any one of them) to the door
2-when 1/2 of the nail peeked through the other side, you would hammer perpendicularly upon it, bending it ninety degrees.
3-drive the remaining section of the nail
4-again, hammer perpendicularly driving the ,now angled, point into the wood

That sucker aint coming out!
It’s dead.

I’m not sure if that’s how the saying originated, but I WAG that it was.
FTR, Z-batten doors are/were very common.

[Topologist]

Charles Dickens, A Christmas Carol

Old Marley was as dead as a doornail.

Mind! I don’t mean to say that I know, of my own knowledge, what there is particularly dead about a doornail. I might have been inclined, myself, to regard a coffin-nail as the deadest piece of iron-mongery in the trade. But the wisdom of our ancestors is in the simile; and my unhallowed hands shall not disturb it, or the Country’s done for. You will therefore permit me to repeat, emphatically, that Marley was as dead as a doornail.

I couldn’t resist. It doesn’t add much to the discussion, but shows that the question in the OP has been considered before…