Adjectives and adjectival nouns?

Hi, both adjectives and adjectival nouns seem the same, they both descibe the noun, so what is the difference between the two group?

Yoroshiku onegaishimasu!

Are you referring to the "i-adjectives" and "na-adjectives"? If so, they take different forms (conjugate differently, so to say), particularly when they are used as predicate of a sentence. They "behave" differently grammatically, so to say.

For example, take "i-adjective" (probably what you are referring to as "adjective") of "utsukushii" (beautiful).

- Utsukushii nagame desu. (It is a beautiful view. In polite speech)
- Utsukushii nagame da. (The same in casual speech).

If used in a predicate:
- Koko kara no nagame wa utsukushii desu. (The view from here is beautiful. In polite speech)
- Koko kara no nagame wa utsukushii. (The same in casual speech.)

They conjugate:
utsukushii (is beautiful), utsukushiku nai (is not beautiful)
utsukushikatta (was beautiful), utsukushiku nakatta was not beautiful)
..so "i-adjective" contain the "be verb" in it.


Take then "na-adjective," "kirei-na" which means, pretty/beautiful.
- Kirei na nagame desu. (It is a pretty view, in polite speech)
- Kirei na nagame da. (The same in casual speech).
You need to have the "-na" when it comes before a noun.

If used in a predicate:
- Koko kara no nagame wa kirei desu. (The view from here is pretty, in polite speech)
- Koko kara no nagame wa kirei da. (The same in casual speech.)

They conjugate:
kirei da/desu (is pretty, in casual/polite speech),
kirei dewa nai/arimasen (is not pretty),
kirei datta/deshita (was pretty),
kirei dewa nakatta/arimasendeshita (was not pretty)
...so "na-adjecive" needs the "-na" to describe a noun when it comes before a noun, and you need to add the be-verb when used as predicate.

Ohh okay thanks. But for the book that I am using to study, there is a part with the title "adjectival noun", in which na and i adjectives are under, and another titled just "adjectives".

Also, may i know why it is called adjectival noun and not just adjective?

Thanks in advance. Yoroshiku onegaishimasu

Then I don't know why they call both "na-" and "i-adjectives" together as adjectival noun :( I am not familiar with that textbook. Then what do they list under "adjectives"?

I always thought that only the "na-" adjectives are referred to as "adjectival nouns," because they "behave" like nouns, such as the use of "desu" or "da" after it to make it a predicate.