"I Do Not Think It Means What You Think It Means"

Inigo Montoya's well-known caution to Vizzini might have a little problem when it comes to these words on a list at Mental Floss -- because they are their own antonyms, or opposites.

Unless carefully deployed, they can offer a sentence whose meaning contradicts the intended meaning entirely. While context can sometimes help, it's not always a guide for some of the words on the list, such as No. 7. You may try to make your meaning of the word "trim" clearer by saying, "trim the tree," but you still leave open the question of whether or not you are decorating it or pruning it.

This effect, of course, is different from the way that politicians use words to mean the opposite of what they say. They will often use words that have a fairly clear meaning, but they will use them to imply an entirely different conclusion by the technique known as "lying."