Can refer to someone who fails in a competition or endeavor.
A pesar de sus esfuerzos, Juan se convirtió en un fallador en el torneo de ajedrez.
Despite his efforts, Juan became a loser in the chess tournament.
A pesar de su esfuerzo, se siente como un fallador en cada examen que presenta.
Despite his effort, he feels like a loser in every exam he takes.