Do you hyphenate third-world

The term "third world" is typically not hyphenated when used as a noun or adjective in modern contexts. However, some style guides may allow for "third-world" as an adjective when it precedes a noun, such as "third-world countries." It's important to consider the context and the style guide you are following. In general, it's advisable to use the term "developing countries" for a more accurate and respectful description.