simple past tense and past participle of constrain
"After being constrained by strict rules, he could not attend the meeting."
In plain English: To constrain means to force someone or something into staying within strict limits so they cannot move freely.
"The tight budget constrained our ability to buy new equipment for the office."
lacking spontaneity; not natural
"a constrained smile"
"forced heartiness"
"a strained smile"
Kept within close bounds; confined.
"The prisoners were constrained to their cells and forbidden from leaving at any time."
In plain English: Constrained means being limited by rules, space, or other things that stop you from doing what you want to do.
"The budget was too constrained to allow for any new projects this year."