Dictionary.net

In a contract, a promise by one party not to hold the other party responsible if the other party carries out the contract in a way that causes damage to the first party. For example, many leases include a hold harmless clause in which the tenant agrees not to sue the landlord if the tenant is injured due to the landlord’s failure to maintain the premises. In most states, these clauses are illegal in residential tenancies, but may be upheld in commercial settings.

a term that denotes "no responsibility" where a person is excused form obligation and liability.