An adhesion contract is a contract balanced in favor of one party over the other that one can assume it was not entered into on equal bargaining grounds. Adhesion contracts are usually formed when one person is in a superior bargaining position and pressures the other party into a contract with unfair or oppressive terms.
For example, a rich landlord dealing with a poor tenant who has to accept a lease on a take it or leave it basis, no matter how restrictive or burdensome, since the tenant cannot afford to move. A consumer making a minor purchase is usually in no position to negotiate terms with a big multinational manufacturer. An adhesion contract can give the person in the unfavorable bargaining position an excuse for invalidating the contract.
"Generally, an adhesion contract is defined as a standardized contract form offered to consumers of goods and services on essentially a 'take it or leave it' basis without affording the consumer a realistic opportunity to bargain and under such conditions that the consumer cannot obtain the desired product or services except by acquiescing in the form contract." Pendergast v. Sprint Nextel Corp., 2010 U.S. App. LEXIS 79 (11th Cir. 2010)