A person who has been compromised or proven themselves unreliable, untrustworthy, a liability, and generally
useless. Someone who has fallen from grace, and is generally ostracized. Someone who destroys themselves or others or causes great harm due to acts of
stupidity, hubris, vanity, greed or negligence. For example, Icarus flew too close to the sun, melting his wings, and fell to his
death.
Surprisingly, this word is used quite often in English-speaking countries, but does not appear in mainstream dictionaries. Some examples of popular references are Porcupine
Tree's album entitled "Deadwing", and used in "Walking Dead" when Martinez refers to the Governor as a 'deadwing'.
After falling asleep on guard duty for the third
time, Billy had become a deadwing, and was no longer trustworthy for guard duty.
Barney was a deadwing and could no longer be allowed to carry a
gun after it went off and shot Otis, who was passed out
drunk in a nearby jail cell.
They're making that deadwing Johnny sweep floors after he drove the forklift off the loading dock.
This is the third
bar Billy's got us thrown out of tonight, so as far as I'm concerned, he's just a deadwing.