A more thorough explanation:

Imprest money is a payment given to a soldier or sailor when they first join the military. This money is meant to help them with any immediate expenses they may have, such as buying new clothes or equipment.

For example, if a soldier enlists in the army, they may receive imprest money to help them purchase their uniform and other necessary items. This money is usually deducted from their future paychecks.

Another example is if a sailor is impressed into service, meaning they are forced to join the navy. They may receive imprest money to help them with any expenses they have before they are officially enlisted.

Overall, imprest money is a way to help new military members get started and ensure they have what they need to begin their service.