What part of speech is the word proper?

The word "proper" can be a few different parts of speech, depending on how it's used in a sentence:

* Adjective: Describes a noun. Example: "She wore a proper dress for the occasion."

* Adverb: Modifies a verb, adjective, or another adverb. Example: "He didn't do it properly."

* Noun: Refers to something that is right or appropriate. Example: "That's not the proper way to do it."

So, without context, it's impossible to determine the specific part of speech.