This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Not controlled or held in check; immoderate: unrestrained exploitation of natural resources.

adj. Free of constraint; spontaneous and natural: an unrestrained laugh.

adj. immoderate; not restrained or held in check

adj. spontaneous, natural and informal; unconstrained

Not restrained; not controlled; not confined; not hindered; not limited.

Licentious; loose.

adj. not subject to restraint

adj. marked by uncontrolled excitement or emotion

"The joint Guardian-LSE Reading the Riots project has shown that the interpretation of the riots as an expression of unrestrained greed and lawlessness is only a partial account."

exuberant    extravagant    unchecked    ungoverned    unbridled    freewheeling    highflying    excessive    unlaced    overweening   

restrained   

unbridled    rampant   

restrained    restrain   

unrestrainedly    unrestrainedness   

Refrained    abstained    arraigned    ascertained    attained    brained    campaigned    caned    chained    complained   

unbridled    uncontrolled    unbounded    reckless    irrepressible    boyish    boisterous    ungovernable    unfettered    unchecked