the.com/loser

means A person defined, in the speaker's judgment, by chronic failure, ineptitude, or being generally pathetic — less about one loss than a permanent losing streak as identity.

from Straightforward agent-noun stuff: 'lose' (from Old English 'losian,' to perish or be destroyed, itself tied to 'los,' meaning destruction or loss) plus the '-er' that turns a verb into 'one who does it.' The literal sense — one who loses a contest or bet — is old, but the sharper insult, 'pathetic, habitual failure as a type of person,' is a 20th-century American development, with slang dictionaries catching it hardening into schoolyard-grade contempt by the mid-1900s and exploding alongside teen-movie culture by the 1980s-90s.