ring-in

ring-in (plural ring-ins)

1. A replacement made at the last minute, often in a sporting context.
2. A racehorse or greyhound fraudulently substituted for another in a race.
3. An outsider.
   • 1967, Elspeth Huxley, Their Shining Eldorado: A Journey through Australia, page 97:

     "But I couldn't get into an underground contract party because I'm a ring-tail, or ring-in." That means an outsider, one not born in Broken Hill.

4. A person pretending to be someone else; an imposter.

• nigrin, rining