Ringer (noun)

1. A person or thing that is a near match to another.
2. A person who is entered in a contest under false pretenses to make it more difficult for the legitimate competitors.

Origin:

Mid 19th century: from ring + -er1.

Examples:

1. The imposter was a ringer for the famous actor.
2. The new car was a ringer for the old model.
3. He was accused of being a ringer in the race.
4. The team's new player was a ringer for a professional player.
5. The counterfeit painting was a ringer for the original.