Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
constrain, restrain (vv.)
To constrain means “to hold onto, to confine within bounds” and, combined with to, “to compel or oblige,” as in They were constrained to comply with the government’s request. To restrain means “to control, to hold back, to deprive of liberty, and to restrict.” In some senses constrain tends to force the person or thing constrained to do something, whereas restrain in some senses tends to immobilize or prevent the person or thing restrained from doing something. In other senses, the two words’ meanings are nearly identical.
