The adjective いい[ii](good, nice) is a bit of a special case, since both the and the ending change shape.
いい → よく
ii → yoku
good, nice → well, a lot, carefully, often
Japanese Articles
How to turn Japanese adjectives into nouns and adverbs?
By: Mayumi Ito Tue Jun 09 2026
In English, a lot of and come from . For example, the adverb “slowly” is built from the adjective “slow,” and the noun “kindness” is built from the adjective “kind.” In Japanese, it’s also possible to turn adjectives into adverbs and nouns! Just like in English, this is mostly done by adding or changing endings. For example:
Adjective → Adverb
安い → 安く
yasui → yasuku
cheap → cheaply
Adjective → Noun
高い → 高さ
yasui → yasusa
high → height
In this post, we’ll talk about how to turn different kinds of Japanese adjectives into nouns and adverbs. Along the way, we’ll talk about how the different ways to do so can impact the meaning or grammar of the word you create. Let’s have a look!
How to make Japanese adverbs from adjectives?
In Japanese, you can usually turn an adjective into an adverb with an ending: either 〜く[ku] or 〜に[ni]. Typically 〜く[ku] is added to i-adjectives while 〜に[ni] is added to na-adjectives. Let’s have a look at exactly how you can use these two endings.
Adverbs that come from i-adjectives
To turn an i-adjective into an adverb, change the ending 〜い[i] to 〜く[ku].
安い → 安く
yasui → yasuku
cheap → cheaply
早い → 早く
hayai → hayaku
early (adj) → early (adv.)
→ Use 早い for a phrase like “early morning” and 早く for a phrase like “arrive early.”
Tip
Here are some examples illustrating how you might use these three adverbs in a sentence. Notice that, like an adverb, they provide additional information about an action or situation instead of a noun!
友達からギターを安く買いました。
Tomodachi kara gitā o yasuku kaimashita.
I bought a guitar cheaply from a friend of mine.
今朝は早く起きた。
Kesa wa hayaku okita.
I got up early this morning.
週末はよくテニスをします。
Shūmatsu wa yoku tenisu o shimasu.
I often play tennis during weekends.
Adverbs that come from na-adjectives
To turn a na-adjective into an adverb, just add 〜に[ni] directly to the dictionary form.
静か → 静かに
shizuka → shizukani
quiet, silent → quietly, silently
上手 → 上手に
jōzu → jōzuni
good, skillful → well, skillfully
Here are some examples of how you can use these adverbs in a sentence.
子供たちは静かに本を読んでいる。
Kodomotachi wa shizukani hon o yonde iru.
The children are quietly reading books.
ニックさんは上手に日本語を話します。
Nikku san wa jōzuni nihongo o hanashimasu.
Nick speaks Japanese well.
How to turn Japanese adjectives into nouns?
In Japanese, there are three main ways to form a noun from an adjective:
Add the suffix 〜さ[sa]
Add the suffix 〜み[mi]
Delete the ending 〜い[i] → color adjectives only!
You’ll use each method in slightly different circumstances. Let’s go through them one-by-one!
When to add 〜さ [sa] to an adjective?
We use the Japanese suffix 〜さ[sa] much like you might use the ending “-ness” in English: it is added to an adjective to turn it into a noun referring to a quality. We’ll often use these nouns to talk about some measure of that quality, much like you might measure something’s “freshness” or “happiness.”
You can add this ending to the of most i-adjectives and some na-adjectives. Remember, the stem of a na-adjective is its dictionary form, but to find the stem of an i-adjective you’ll need to remove the 〜い[i] ending!
i-adjective
高い → 高さ
takai → takasa
high, tall → height
na-adjective
大切 → 大切さ
taisetsu → taisetsusa
precious, important → preciousness, importance
Here are some examples of how you might use these 〜さ[sa] nouns in a sentence:
東京タワーの高さはどのくらいですか。
Tōkyō tawā no takasa wa donokurai desu ka.
How high is Tokyo Tower?
lit. As for the height of Tokyo Tower, how much is it?
子供たちに命の大切さを教えよう。
Kodomotachi ni inochi no taisetsusa o oshieyō.
Let’s teach children the preciousness of life.
Tip
Again, the i-adjective いい[ii](good, nice) has a stem change as well:
いい → よさ
ii → yosa
good, nice → goodness
When to add 〜み [mi] to an adjective?
You can add the suffix 〜み[mi] to the stem of some i-adjectives to create a noun that indicates a sense, feeling, place, or state. Please note that the number of i-adjectives that take 〜み[mi] is limited. Compare the meanings of these nouns to nouns created using 〜さ[sa].
Adjective | Noun with み[mi] | Noun with さ[sa] |
|---|---|---|
痛い itai painful | 痛み itami pain | 痛さ itasa painfulness |
悲しい kanashii sad | 悲しみ kanashimi sorrow | 悲しさ kanashisa sadness |
深い fukai deep | 深み fukami depth, a deep spot | 深さ fukasa deepness |
And here are some examples of these words in sentences.
膝の痛みはまだありますか。
Hiza no itami wa mada arimasu ka.
Do you still have pain in your knees?
小川を渡るとき、深みにはまりそうになった。
Ogawa o wataru toki, fukami ni hamarisōni natta.
When crossing the creek, I almost fell into a deep spot.
When to remove い [i] from a color adjective?
In English, you can use any color adjective as an adjective (“a red dress”) or a noun (“the red of the dress”) without changing the word at all. In Japanese though, you’ll need to remove the ending い[i] to use a color adjective as a noun.
The six i-adjectives that describe basic colors in Japanese are listed in the table below.
Color adjectives | Color nouns | English |
|---|---|---|
赤い[akai] | 赤[aka] | red |
青い[aoi] | 青[ao] | blue |
白い[shiroi] | 白[shiro] | white |
黒い[kuroi] | 黒[kuro] | black |
黄色い[ki’iroi] | 黄色[ki’iro] | yellow |
茶色い[chairoi] | 茶色[chairo] | brown |
You can use the color adjectives to describe a noun just like any other i-adjective: just put the dictionary form directly before the noun. But if you want to describe the color of something using a color noun, you’ll need to add の[no] between the color noun and the thing you’re describing.
i-adjectivenoun
赤いバラ
akai bara
red rose
color nounの [no]noun
緑の丘
midori no oka
green hill
Tip
There are other color words in Japanese, but these are all derived from the words above. Some of these derived color words are na-adjectives, such as 真っ赤な[makkana](bright red) and some are i-adjectives, such as 薄赤い[usuakai](pale red). Even more are nouns, like 空色[sorairo](sky-color). Wondering how you can describe other colors in Japanese? Check out our post on how to describe colors in Japanese!
To sum up
In this article, we looked at how to make adverbs and nouns out of Japanese adjectives. Here are the biggest takeaways:
To make an adverb from an adjective:
i-adjectives → change the ending 〜い[i] to 〜く[ku]
na-adjectives → add 〜に[ni] to the dictionary form
To make a noun from an adjective:
add 〜さ[sa] to the adjective stem → like adding “-ness” in English
add 〜み[mi] to the stem of some i-adjectives → describes a sense, feeling, place, or state
remove 〜い[i] from i-adjectives for colors
Ready to practice what you’ve learned? Check out our adjectival nouns and adverbs activities! Or, if you’d rather keep learning, check out our other posts on Japanese adjectives!
