con·strain / kənˈstrān/ • v. [tr.] (often be constrained) severely restrict the scope, extent, or activity of: agricultural development is constrained by climate. ∎  compel or force (someone) toward a particular course of action: children are constrained to work in the way the book dictates. ∎  [usu. as adj.] (constrained) cause to appear unnaturally forced, typically because of embarrassment: acting in a constrained manner. ∎ poetic/lit. confine forcibly; imprison. ∎ archaic bring about (something) by compulsion..DERIVATIVES: con·strain·ed·ly / -nədlē/ adv.

constrain force, compel, confine forcibly. XIV. — OF. constraindre, pres. stem constraign- (mod. contraindre) :- L. constringere bind tightly together; see CON- and STRINGENT.
So constraint †affliction XIV; compulsion, confinement XVI; restraint of natural feelings XVIII. — OF. constrainte, fem. pp. sb. f. constraindre.