What part of speech is thin?

"Thin" can be multiple parts of speech, depending on how it's used in a sentence:

* Adjective: Describing a quality or state. Example: "The paper is thin."

* Verb: To make something thinner. Example: "She thinned the paint with water."

* Adverb: Describing the manner of an action. Example: "The fog thinned as the sun rose."

Let me know if you have a specific sentence in mind, and I can tell you which part of speech it is in that context!