Definition of ringers:
(n) :
(sports) A person highly proficient at a skill or sport who is brought in, often fraudulently, to supplement a team.
(n) :
(slang) Any person or thing that is fraudulent; a fake or impostor.
(n) :
(horse racing) A horse fraudulently entered in a race using the name of another horse.
(n) :
A person, animal, or entity which resembles another so closely as to be taken for the other; a look-alike (now usually in the phrase dead ringer).
(n) :
Someone who rings, especially a bell ringer.
(n) :
(games) In the game of horseshoes, the event of the horseshoe landing around the pole.