satisfy

Satisfy is a transitive verb with several related senses. Most commonly, it means to fulfill a need, desire, expectation, or requirement, as in meeting criteria or completing obligations. It can also mean to provide enough of something to satisfy or quiet a demand, or to appease someone’s anger or complaints, as in satisfying a protest.

Etymology traces satisfy to Old French satisfaire, from Latin satisfacere “to make enough,” from satis “enough” and facere “to do.” The word has been in use in English since the late Middle Ages.

Usage across fields varies. In everyday language, to satisfy means to make content or deliver what is required (for example, a meal that satisfies hunger). In law and contracts, to satisfy terms or conditions means to meet and comply with them. In logic and computer science, a formula is satisfiable if there exists an interpretation in which the formula is true; a model that makes the formula true is said to satisfy it. The satisfiability problem (SAT) concerns determining whether a given boolean formula is satisfiable, a central topic in computational complexity (the general case is NP-complete).

In psychology and philosophy, satisfaction describes the subjective sense of contentment that follows from meeting aims or desires. The noun satisfaction and the adjective satisfied are common derivatives used to discuss fulfillment and contentment.