A replacement for
someone's ex-boyfriend or ex-girlfriend who looks so much
like the ex, it's uncanny. Sometimes
done deliberately to piss off the ex.
One Dude to Another: Did you see that chick with Nick?
Another: Yeah I saw her and did a double take, I thought it was his ex, not his new chick.
One Dude: She looks so much
like his ex, she's a fuck-alike.
Another: Wait till the ex sees the fuck-alike. She
will throw a
fit.