IPA: /ˈswɒpə/
KK: /ˈswɑːpər/
A person or thing that exchanges one item for another.
The swapper traded his old video game for a new one at the market.
Swapper → It is formed from "swap" (of uncertain origin, possibly from Old Norse *svipa*, meaning to move or change) and "-er" (meaning a person who). A swapper is a person who engages in the act of exchanging or changing something.
Think of someone who 'changes' or 'moves' things around — that's what a swapper does.