Source : Webster's Revised Unabridged Dictionary (1913)

Constrain \Con*strain"\, v. t. [imp. & p. p. {Constrained}; p.
   pr. & vb. n. {Constraining}.] [OF. constraindre, F.
   contrainde, L. constringere; con- + stringere to draw tight.
   See {Strain}, and. cf. {Constrict}, {Constringe}.]
   1. To secure by bonds; to chain; to bond or confine; to hold
      tightly; to constringe.

            He binds in chains The drowsy prophet, and his limbs
            constrains.                           --Dryden.

            When winter frosts constrain the fields with cold.
                                                  --Dryden.

   2. To bring into a narrow compass; to compress.

            How the strait stays the slender waist constrain.
                                                  --Gay.

   3. To hold back by force; to restrain; to repress.

            My sire in caves constrains the winds. --Dryden.

   4. To compel; to force; to necessitate; to oblige.

            The love of Christ constraineth us.   --2. Cor. v.
                                                  14.

            I was constrained to appeal unto C[ae]sar. --Acts
                                                  xxviii. 19.

   5. To violate; to ravish. [Obs.] --Shak.

   6. To produce in such a manner as to give an unnatural
      effect; as, a constrained voice.

   Syn: To compel; force; drive; impel; urge; press.

Source : WordNet®

constraining
     adj : restricting the scope or freedom of action [syn: {confining},
            {constrictive}, {limiting}, {restricting}]