A backer is someone who financially supports a player in exchange for a share of winnings.
Explanation. In tournament poker, a backer bankrolls a player by covering their buy‑in costs. In exchange they receive a pre‑agreed share of any winnings. This arrangement is common among players without sufficient bankroll or those wanting to spread risk. Backing involves trust and contract etiquette, and knowing how to stake or be staked is valuable knowledge at the intermediate bankroll management level.