unbuttoned

动词 unbutton:

1. undo the buttons of
   同义词：unbutton

形容词 unbuttoned:

1. not buttoned
   同义词：unfastened
2. not under constraint in action or expression
   同义词：unlaced

un.but.ton.ed

adj.（形容词）
Not buttoned.
无扣的
Free and unrestrained in expression:
无拘无束的：在表达上自由且无限制：
例句：
unbuttoned humor.
极为幽默