These words have several meanings, but here are some differences that may help you: Constraint — this usually refers to limitations imposed by a situation. Example: The engineers had to design the product to meet strict size, weight, and cost constraints. Restraint — this usually refers to a physical thing that keeps a person or thing from moving. Example: “Handcuffs are a form of restraint.” “Restraint” can also refer to having self-control over one’s temper. Example: “Even though he was a jerk to her, she showed great restraint and treated him politely.” Restriction — this usually refers to a limitation on action imposed by a person in authority. Example: “The government has imposed harsh restrictions on freedom of speech.”