Verb

To reverse the effects of an action.

Fortunately, we can undo most of the damage to the system by the war.

* {{quote-news

, year=2011 , date=October 15 , author=Michael Da Silva , title=Wigan 1 - 3 Bolton , work=BBC Sport citation , page= , passage=But Wigan undid their good work by conceding an avoidable second goal deep into first-half injury time.}}

To unfasten.

Could you undo my buckle for me?

(figuratively) to be heading for or to cause a downfall

* 1611 ,

Woe is me, for I am undone !

Verb

(en verb)

To undo or open a lock or something locked by, for example, turning a key, or selecting a combination.

To obtain access to something.

*{{quote-magazine, date=2013-07-20, volume=408, issue=8845, magazine=(The Economist)

, title= Welcome to the plastisphere , passage=Plastics are energy-rich substances, which is why many of them burn so readily. Any organism that could unlock and use that energy would do well in the Anthropocene. Terrestrial bacteria and fungi which can manage this trick are already familiar to experts in the field.}}

To disclose or reveal previously unknown knowledge.

To be or become unfastened or unrestrained.

*

He had come straight up without mishap or swerving off his course, and his shut teeth unlocked .