Use unconstrained to describe not holding back, like the frenzied fans whose team just won the championship showing their unconstrained joy.
In the adjective unconstrained the prefix un-, meaning “not,” meets constrained, meaning “restricted” or “limited.” So something that’s unconstrained means "without limits or restrictions," like an unconstrained child who doesn't have to follow rules, the unconstrained power of a dictator, or an unconstrained dog running loose.
