Money a tenant gives a land­lord at the beginning of the tenancy to protect the landlord in case the tenant fails to comply with the terms of the lease; the landlord may retain all or part of the deposit to cover unpaid rent or repair costs at the end of the tenancy. According to the Minnesota Landlord-Tenant Act, a security deposit is any deposit of money the function of which is to secure the perfor­mance of a residential rental agreement (not including an advance payment of rent).