security deposit
noun [ C ]
ukus PROPERTY, COMMERCE
an amount paid when you agree to rent a house, apartment, etc., which its owner can keep if you leave before the end of the agreement or damage the property:
The site offers residents help on how to get a landlord to make repairs or return a security deposit.
FINANCE, COMMERCE
an amount that someone selling something asks for, which they can keep if the buyer later decides not to buy:
The plan offers homeowners solar power energy for a security deposit of £1,000, rather than the full £20,000 installation cost.