Constraint \Con*straint"\, n. [OF. constrainte, F. constrainte.]

The act of constraining, or the state of being constrained; that which compels to, or restrains from, action; compulsion; restraint; necessity.

Long imprisonment and hard constraint. --Spenser.

Not by constraint, but by my choice, I came. --Dryden.

Syn: Compulsion; violence; necessity; urgency.

Usage: Constraint, Compulsion. Constraint implies strong binding force; as, the constraint of necessity; the constraint of fear. Compulsion implies the exertion of some urgent impelling force; as, driven by compulsion. The former prevents us from acting agreeably to our wishes; the latter forces us to act contrary to our will. Compulsion is always produced by some active agent; a constraint may be laid upon us by the forms of civil society, or by other outward circumstances. --Crabb.

Source: Webster's Revised Unabridged Dictionary (1913)