fun - part of speech

Compared to other languages, English is in practice pretty indifferent with regards to parts of speech. The lines are often blurry. I'm curious about the following phrase:

It's fun.

Usually, I'd think that "fun" is a noun. For instance I can have lots of it. However, there are phrasings where it is used much like a qualifier.

It was a fun ride.

Just looking at the structure, it could be either an adjective or a noun in the phrase in question.

It's fun/milk. It's fun/nice.

My first impulse was "noun" but seeing how there is no article and how most phrasings that express roughly the same would use an adjective, I am not so sure anymore. Here are my questions.

• What part of speech is "fun" in the phrase?


• Do native speakers clearly perceive it as noun or adjective respectively or would both readings make sense on an intuition level?

Answer

Indifferent is not the correct word to describe the way native English speakers regard parts of speech; it's more like flexible:

In the unambiguous expression:

the children enjoyed the fun and games

Fun is a noun.

In the unambiguous expression:

the children enjoyed the fun games

Fun is an adjective.

In the ambiguous expression:

it's fun

The larger context will determine the part of speech:

Fun is renaming it as a predicate noun.

or

Fun is describing it as a predicate adjective.

As long as people can perceive, use and interpret parts of speech properly, it is not so important to label them. We teach our children to label parts of speech so that they can learn to speak, read and write properly. As instructors, the labels remain supremely relevant to us, but once our students can speak, read and write, the labels quickly become less relevant to them. Those who never discuss parts of speech, tend to forget the significance of the labels, because they don't need the labels to communicate.