подразбиращ се договор(Black's Law Dictionary - A contract that the parties presumably intended as their tacit understanding, as inferred from their conduct and other circumstances. - Also termed contract implied in fact. алешаBG)
квазидоговор(Black's Law Dictionary - An obligation created by law for the sake of justice; specif., an obligation imposed by law because of some special relationship between the parties or because one of them would otherwise be unjustly enriched. - An implied-in-law contract is not actually a contract, but instead is a remedy that allows the plaintiff to recover a benefit conferred on the defendant. - Also termed contract implied in law; quasi-contract; constructive contract. алешаBG)