Japanese words for colors are predominantly no-adjectives, in contrast other basic adjectives, which are primarily i-adjectives and na-adjectives. As we go through the Japanese color words, there are also a couple of important points we can cover regarding their use.
Language and Color
If you ask several people what they would call a particular color, you're likely to get a variety of responses. This is because words for colors are inherently arbitrary, since there are an unlimited number of ways to break up spectrum of red to violet, not to mention differences in brightness and saturation.
It should come as no surprise, then, that languages also vary in how they name colors, even very basic colors. As it turns out, the basic colors in Japanese are very similar to those in English, but there is one major difference in the blue-green area of the spectrum.
The primary colors in Japanese are all i-adjectives, which agrees with the idea that i-adjectives tend to represent more basic concepts than na-adjectives.
The word for "color" is いろ (iro), which you can see embedded in kiiroi (yellow).
Actually, even kiiroi could be considered less basic than the other four, since it requires the kanji for "yellow color" (黄色い） rather than just one kanji (赤い、青い、白い、黒い）. We'll discuss aoi (blue/green) more in a moment.
As with any i-adjective, you simply place the word in front of the noun being colored.
|あかいくるま||akai kuruma||a red car|
|きいろいほん||kiiroi hon||a yellow book|
|しろいマグ||shiroi magu||a white mug|
|くろいペン||kuroi pen||a black pen|
However, when you want to say that something is some color (the predicate function), you must use the no-adjective (noun) equivalent of the word.
Thus we have akai booru (a red ball), but:
|ボールは あかです。||Booru wa aka desu.||The ball is red.|
Other color words are normal no-adjectives, so these five are really the exception rather than the rule. Fortunately, the rule itself is without exception: when using primary colors to modify a noun, use the i-adjective form; otherwise, use the no-adjective form.
You would also use aka to refer to "the color red", which is similar to how color words in English are used as both nouns and adjectives.
Finally, the noun forms are also used in some compound words.
|くろねこ||kuroneko||a black cat|
However, due to the influence of Kanji, compound words including colors generally use the on-yomi (Chinese reading) of the character rather than the independent words.
Blue and Green
Although it seems strange to westerners, ao (or aoi) can mean either "blue" or "green" in Japanese. Actually, it refers to this entire spectrum, and our blue, teal, and green would all be considered shades of ao.
So occasionally in places where English speakers would use "green", Japanese people would instead use ao.
|くさは あおです。||Kusa wa ao desu.||The grass is green.|
|あおしんごう||aoshingo||green light (traffic signal)|
Fun fact: Japanese traffic lights are indeed somewhat bluish compared to those in North America.
Japanese people also consider the ocean to be ao, which makes sense considering that seawater is just as green up close as it is blue from a distance.
Other Basic Colors
The remaining colors are all no-adjectives (nouns) and have no further complications. Here are the ones you will want to memorize.
|こん||kon||dark blue||a shade of ao (blue/green)|
|みずいろ||mizuiro||light blue||literally "water color", a shade of ao|
|みどり||midori||green||same as in the English sense – bright green and dark green, a shade of ao|
|むらさき||murasaki||violet/purple||there is no distinction between "violet" and "purple" in Japanese (some English speakers also make no distinction)|
|オレンジ（オレンジいろ）||orenji (orenjiiro)||orange||a borrowed word, a similar color is daidaiiro (dark orange)|
|ピンク||pinku||pink||a borrowed word, a similar color is momoiro "peach color"|
|ちゃいろ||chairo||brown||literally "tea color"|
|はいいろ||haiiro||grey||literally "ash color", another word is nezumiiro "mouse color"|
|きんいろ||kin'iro||gold||kin is the metal "gold"|
|ぎんいろ||gin'iro||silver||gin is the metal "silver"|
Again, the iro found in many of these words is the root word for "color".
|みどりのかばん||midori no kaban||a green bag|
|かえるは みどりです。||Kaeru wa midori desu.||Frogs are green.|
To ask "what color" something is, you can use the question word nani-iro.
|なにいろですか。||Nani-iro desu ka?||What color is it?|
|オレンジです。||Orenji desu.||It's orange.|
And that's all there is to it.