な-adjectives

Now let's look at な-adjectives, named after the な that comes after them. な adjectives are simple words that look like nouns, but they can be used attributively to describe other nouns by connecting them with the な “particle”.

バカな子供
Stupid kid

大好きな人
Beloved person

Now that we learned what relative clauses are, it’s good to learn that the term “attributely” basically means “as a relative clause”.

At the end of sentences, な-adjectives can look like nouns, and just like nouns they can end sentences with だ

この部屋は静かだ
This room is quiet.

The な “suffix” is basically what allows な adjectives to work attributively in a sentence. You might have noticed this <adj>な<noun> structure looks very similar to <noun>の<noun> structure we’ve already seen in Lesson 5. な can even be used this way with some normal nouns, not just な-adjectives, but it is a bit of an exceptional usage with some specific nuance that we don’t need to worry about now.

魔法の世界
World of magic

魔法な世界
Magic-ish world

魔法 is a noun (magic), and does not normally take な like this, but some authors might write something like this to give it a special vibe.

Going back to normal な-adjectives, they should be considered separate from nouns, and dictionaries do keep them as such. They clearly distinguish nouns (名詞) and な-adjective (形容動詞) as different categories. While a lot, if not most, of な-adjectives are also nouns, some of them aren’t, and cannot be used that way. For example, you cannot attach case marking particles directly to them.

元気な人
An energetic person

元気が出る
To feel energized (lit. energy comes out)

静かな人
A quiet person

*静かが？？？
(ungrammatical sentence fragment)

In the example above, 元気 works both as a な-adjective and as a noun, but 静か can only work as a な-adjective.

Some resources also recognize so-called の-adjectives, which are just nouns that are a bit special because they can turn into having an adjective-like meaning using の instead of な.

英語の本
English-language books. (NOT "books of english")

普通の人
A normal person.