What part of speech is fun in this sentence - It was fun?

In the sentence "It was fun", the word "fun" is acting as an adjective.

Here's why:

* Adjectives describe nouns. In this sentence, "fun" describes the pronoun "it."

* "Fun" modifies the noun "it" by telling us what kind of "it" it was. We understand that "it" was enjoyable or pleasurable.

Let me know if you'd like to explore other examples of adjectives!