Is the word just a noun?

No, the word "just" is not just a noun. It can function as several different parts of speech:

* Adverb: This is its most common usage. It means "only" or "exactly."

* Example: "I just want to go home."

* Adjective: This means "fair" or "right."

* Example: "That's a just punishment."

* Interjection: This is a word used to express emotion, usually surprise.

* Example: "Just! I can't believe you did that."

Let me know if you'd like more examples!