1. The use of force to influence or to prevent an action.
2. The state or quality of being compelled to do or not to do something; restricted liberty.
3. The threat or use of force to control the thoughts or behavior of others.
4. The state of being restricted or confined within prescribed bounds: "My brother soon tired of the constraint of military life."
5. Anyone who restricts, limits, or regulates; a check: "She ignored all moral constraints in her pursuit as head of the company."
6. Embarrassed reserve or reticence; awkwardness: “Thke constraints between the two vanished and they started to discuss the situation.”