What part of speech is complaining?

"Complaining" can be a few different parts of speech depending on how it's used in a sentence:

* Verb: This is the most common usage. Example: "She was complaining about the weather."

* Noun: It can be a noun referring to the act of complaining. Example: "The complaining was getting tiresome."

* Gerund: This is a verb form used as a noun. Example: "I'm tired of complaining."

To determine the correct part of speech, look at how the word is used in the specific sentence.