constraint

noun5

1. •
   Something that constrains; a restriction.

   • An engineer must recognize the difference between a constraint (to work within) and a problem (to be eliminated via resolution).
2. •
   A condition that a solution to an optimization problem must satisfy.
3. •
   A linkage or other restriction that maintains database integrity.
4. •
   An irresistible force or compulsion.

   • They confessed, but only under severe constraint.
5. •
   The repression of one's feelings.