Prenup is a colloquial American term for a prenuptial agreement - an agreement entered into by people who intend to marry. In Australia, a prenup is known as a Binding Financial Agreement (or BFA), however most people will still refer to these agreements as prenups.

A "prenup" is a colloquial American term referring to an agreement entered into by people who are proposing to marry. The aim is to exclude either of them going to the Family Court if they ever separate, "protecting" by stating how in the "good times" each person's assets will be divided and how their debts will be repaid if the parties' split.