The words "doesn't" and "don't" are actually negative in expressions. Explicitly, these words mean "does not" and "do not," respectively. These words, grammatically, have the same meaning. But don't it is used in a wider range than doesn't. Fundamentally, the two words are verbs: the negative form of does and do.
Nevertheless, don't is also used as a noun sometimes, basically in the term "dos and don'ts," which means "what is" and "what ought not" to be done. In addition, I would say "don't" is also used as an interjection or exclamation sometimes too.
When it is used in this form, it means "to stop." Back to their meanings and used as verbs, you can only use "doesn't" alongside any third person singular pronouns or nouns. Don't can then be used with any other form, such as first-person and second-person plural and singular, and third-person plural.