unconstrained

adjective

1. forced, compelled, or obliged: a constrained confession.
2. stiff or unnatural; uneasy or embarrassed: a constrained manner.

adjective

1. not having any constraints

adjective

1. embarrassed, unnatural, or forceda constrained smile

adj.1640s, from un- (1) “not” + past participle of constrain. Related: Unconstrainedly.