the state of being physically constrained
"dogs should be kept under restraint"
a device that retards something's motion
"the car did not have proper restraints fitted"
the act of constraining; the threat or use of force to control the thoughts or behavior of others
"The government imposed a severe constraint on the press by using its authority to shut down any newspaper that criticized the regime."
Something that constrains; a restriction.
"The tight budget acted as a severe constraint on our ability to hire new staff."
In plain English: A constraint is something that limits what you can do or how much freedom you have to act freely.
"The tight budget was a major constraint on our ability to hire new staff."
Usage: Use constraint to describe any factor, such as time or resources, that limits your options or actions. It is often confused with the verb constrain, which means to force someone into doing something against their will.
From Middle English constreynt, constreynte, from Old French constreinte, past participle of constreindre ("to constrain"), from Latin cōnstringō (corresponding to the past participle cōnstrictus).