A spendthrift provision is a provision in a trust that prohibits the beneficiary from using the trust assets until a certain event occurs or a certain condition is met. The purpose of a spendthrift provision is to protect the trust assets from the beneficiary's creditors and from the beneficiary's own impulsiveness or inability to manage money.

The provision typically states that the beneficiary does not have the right to access the trust assets until a certain age, such as 21 or 25, or until the beneficiary demonstrates financial responsibility or maturity. Additionally, the trustee may have discretion over disbursement of funds to the beneficiary, rather than the beneficiary having direct access to the funds

It is usually included in trusts that have been set up for the benefit of a person who is likely to have financial difficulties, such as those with a history of overspending or with a drug or gambling addiction. It also is implemented when the creator of the trust wants to ensure that the funds will be used for a specific purpose, such as the beneficiary's education or starting a business.

It's worth noting that spendthrift provisions do not always protect trust assets from creditors and in some jurisdictions, the provision may not be legally enforceable, so it's always best to check with a lawyer if you have any doubt.