Not buttoned:
— The wind picked up the hem of her unbuttoned coat.

synoniem: unfastened.

Roget 748: free, free as air; out of harness, independent, at large, loose, scot-free; left alone, left to oneself.    in full swing; uncaught, unconstrained, unbuttoned, unconfined, unrestrained, unchecked, unprevented^†, unhindered, unobstructed, unbound, uncontrolled, untrammeled.    unsubject^†, ungoverned, unenslaved^†, unenthralled^†, unchained, unshackled, unfettered, unreined^†, unbridled, uncurbed, unmuzzled.    unrestricted, unlimited, unmitigated, unconditional; absolute; discretionary etc. (optional) 600.    unassailed, unforced, uncompelled.    unbiassed^†, spontaneous.    free and easy; at ease, at one's ease; degage [Fr.], quite at home; wanton, rampant, irrepressible, unvanquished^†.    exempt; freed etc. 750; freeborn; autonomous, freehold, allodial^†; gratis etc. 815; eleutherian^†.    unclaimed, going a begging.    ... meer laten zien

Not under constraint in action or expression:
— This unbuttoned and disrespectful age.

synoniem: unlaced.