Marilyn Johnson explored the subculture of obituary scribes in her wonderful 2006 book, The dead beat.
He was dead beat with roaming the streets, without a penny in his pocket, all day long.
The flock must have been dead beat, by the time they got here.
The 4th Brigade got the nearest at Landrecies, but it got there dead beat and then had to fight all night.
You ought to be dead beat after your double spell of the last two days.
I was dead beat, and staggered about to right and left like a drunken man.
He is a dead beat, I thought so before and am sure of it now.
The men at the telephones were dead beat, but cool and collected.
The Adjutant had come in unwounded, but dead beat, and could not say where the Colonel was.
I was that dead beat and tired out that I turned over and went to sleep for another couple of hours.
"worthless sponging idler," 1863, American English slang, perhaps originally Civil War slang, from dead (adj.) + beat. Earlier used colloquially as an adjectival expression to mean "completely beaten" (1821), and perhaps the base notion is of "worn out, good for nothing." It is noted in a British source from 1861 as a term for "a pensioner."
In England "dead beat" means worn out, used up. ... But here, "dead beat" is used, as a substantive, to mean a scoundrel, a shiftless, swindling vagabond. We hear it said that such a man is a beat or a dead beat. The phrase thus used is not even good slang. It is neither humorous nor descriptive. There is not in it even a perversion of the sense of the words of which it is composed. Its origin is quite beyond conjecture. ["Americanisms," in "The Galaxy," January 1878]It also was used of a kind of regulating mechanism in pendulum clocks.
Completely exhausted: My poor ass is draggin' and I'm dead beat (1821+)
To sponge, loaf, etc: Living off interest is not exactly deadbeating
[1863+; fr dead, ''complete, completely'' and beat, ''sponger'']