limitation or restriction.

repression of natural feelings and impulses

to practice constraint.

unnatural restraint in manner, conversation, etc.; embarrassment.

something that constrains.

the act of constraining.

the condition of being constrained.

Linguistics . a restriction on the operation of a linguistic rule or the occurrence of a linguistic construction.

noun

aggression , allowance , permission

noun

a must , coercion , compulsion , driving , duress , goad , hang-up * , impelling , impulsion , monkey * , motive , necessity , no-no , pressure , repression , restraint , spring , spur , suppression , violence , bashfulness , diffidence , embarrassment , humility , inhibition , modesty , reservation , reserve , timidity , arrest , captivity , check , circumscription , confinement , constrainment , cramp , curb , damper , detention , deterrent , hindrance , limitation , strength , limit , stricture , trammel , bond , distress , force , obligation , restriction , shyness