backsie

noun

1. The back.“A mimsy, a clapsy, I roll my hands, touch backsie, My right hand, my left hand, High as the sky, low as the sea, I touch my knee, and my heel, and my toe, And over we go.”
2. The act of taking back or going back on a statement, promise, or agreement.“No backsie no matter what.”
3. A reciprocal action or consequence, such as immediately tagging the player who has tagged one in a game of tag.
4. The act of going through a sequence of moves in reverse.“And then you play Backsies again if you're playing that way.”
5. The act of joining a queue behind a friend rather than at the end of the queue.“To her, the ethical thicket consists of "frontsies and backsies," a phenomenon she noticed in kindergarten.”