Refers to someone who guesses correctly or solves problems.
El acertador del juego logró resolver el enigma antes que los demás participantes, ganando el premio.
The solver of the game managed to solve the riddle before the other participants, winning the prize.
El acertador del concurso recibió un premio por su increíble habilidad para resolver problemas.
The winner of the contest received a prize for his incredible ability to solve problems.