If you often use online social media, you will see many examples of informal English.

One expression that you may wonder about is: "This ain't it, chief."

It is used to tell someone they are wrong about something they posted on social media.

For example, a drink company posted a question asking if people would enjoy pumpkin spice-flavored juice.

Many people answered the question with the same four words: "This ain't it chief," meaning "no."

Many respected grammar books will tell you that "ain't" is "nonstandard English," meaning not usual.

Popular dictionaries have warned against using the word for years.

So, its recent rise in use might make you think it is a new slang word.

However, "aint" has a long, rich history in British and American literature.

The contraction "ain't" is usually a short form of "am not," but it can also mean "is not" or "are not" as well as "have not" or "has not."