What it means
A voidable contract is binding unless and until the disadvantaged party chooses to cancel (rescind) it. The right to cancel usually arises where consent was affected by misrepresentation, undue influence, duress, or unconscionable conduct. Until it is rescinded, a voidable contract is fully enforceable. The right to rescind can be lost — for example, by affirming the contract after learning the truth, or by long delay. This contrasts with a void contract, which had no legal effect from the start.
How it's used
Because the salesperson had lied about the car's history, the buyer's contract was voidable and she chose to rescind it.