WordWeb Online

1. Lacking spontaneity; not natural
   "a constrained smile";
   - forced, strained

1. Limit or hold back; keep within a small range
   - restrain, encumber, cumber [archaic]
    
2. (of laws or regulations) make more restrictive, or impose greater penalties
   - stiffen, tighten, tighten up

See also: affected, unnatural

Type of: bound, confine, limit, restrain, restrict, throttle, trammel

Encyclopedia: Constrained