Quiz: Remember the definition of mal de mer?
mid-14c., "a destroyer," agent noun from lose (v.). Sense of "one who suffers loss" is from 1540s; meaning "horse that loses a race" is from 1902; "convicted criminal" is from 1912; "hapless person" is 1955 student slang.
An unexpectedly bad situation, program, programmer, or person. Someone who habitually loses. (Even winners can lose occasionally). Someone who knows not and knows not that he knows not. Emphatic forms are "real loser", "total loser", and "complete loser" (but not **"moby loser", which would be a contradiction in terms).