English is a stupid language. Really, it is utter bullshit. I am so thankful to have it as my mother tongue, and not had to learn it later in life.
Native speakers, and many of those for whom it is a learned language, will be aware of homonyms; words that are spelled and/or pronounced the same as each other, whilst having different meanings. For example seal, minute or pole are homonyms. Such words can be confusing when read or heard, as the intended meaning may not always be immediately obvious.
Even worse than homonyms, however, are contronyms. These words are not only both spelled and pronounced identically, but their meanings are opposites of each other. Who thought this was a good idea?!
Take, for example, the word fast. The most common usage of this word is to describe movement as being rapid or speedy. Like Usain Bolt. He’s very fast, I’m sure you’ll agree. But there is of course the other meaning of the word; to remain firmly in place. Something which Mr. Bolt had to do prior to running each race. Indeed, he had to go from remaining fast to moving fast.
Aptly, bolt is another contronym. Either one can bolt quickly, as in flee, or they can bolt something in place.
There are many more, too. When the stars are out, they are shining. When a light is out, it is not shining.
You can dust your windowsill when cleaning, or dust a cake with icing sugar.
A cinema will screen (show) movies, but curtains screen (block) a view.
There is an in-exhaustive list here of contronyms in the English language if you learning some more.