Constrained means held back by limits, or stiff and unnatural in manner. Constrained by the budget, a constrained smile, feel constrained.
The first sense is neutral and technical, since every real problem is constrained by something. The second describes a manner and means somebody is holding themselves in.
1adjectiveconstrainedHeld back by limits, or stiff and unnatural in manner.
“Constrained by a tight budget, the school cannot hire any more teachers.”
constrained is a state.