い Adjectives

An Adjective is that part of speech that includes words such as happy, sad, interesting and beautiful. Adjectives modify Nouns and denotes some quality to those nouns or describes other nouns, for example: an interesting book is a book that is distinguished from all other books as being interesting or counterfeit notes describes notes as being counterfeit but not any note in particular.

In Japanese, it is the 〜い ending that gives this type of adjective it's name as an i-adjective; these type of adjectives have the unique way of conjugating into past, non-past, positive and negative forms which is why you'll see them at the predicate also known as the verbal adjective.

There some adjective that end in 〜い but are not i-adjective but instead are known as na-adjective. If an adjective ends in an /ei/ sound (or "ei" in romaji) then it's not an i-adjective but a na-adjective which we will cover in the next lesson.

New Words to Learn

Here are some more words to learn, all of which are i-adjective to help get you started with reading and making sentences. Also, remember from a previous lesson that some Colours are adjectives too.

Changing Tense

The interesting thing about i-adjective is that they can change tense to represent past and non-past forms just like です. Just like in English, there is also no form of future tense in Japanese so that's one less thing to worry about understanding. In English, future events can only be viewed or expressed with the use of a present tense verb.

All you need to do to conjugate i-adjectives is remove that final い character from a word and replace it with the tense type you need to use (みにくい => みにく). The present tense positive form basically does not need to change.

Here is an example of conjugating an i-adjective into each tense form:

Adjective Formality at the Predicate

The other interesting thing about i-adjectives is that they do not need to use です as they complete sentences on their own. Remember before in the What is です (desu) lesson, i-adjectives are one of the four ways to form the Predicate.

Since all the conjugations take place with the i-adjectives themselves and not the です, the です is there for politeness only. When speaking informally, it's fine to end a sentence with the i-adjective, dropping です completely.

Also, I should mention that you should never use the informal だ copula with i-adjectives as だ is used to declare something ("It is") and i-adjectives already have that meaning. Saying ゆたくんは早いだ is wrong because it is using だ with an i-adjective ("It is, It is Yuta who is fast.").

Using です with an i-adjective is okay because while です is viewed as "it is" in English, it actually just adds formality and politeness to a sentence, not "it is". Therefor, です is simply used just for it's politeness only. Just do not conjugate the です, only the i-adjective itself.

Adjectives before a Noun

In previous lessons, we covered just a tiny bit on how the の particle can connect two nouns together such as the sentence 灰色の車 (はいいろのくるま) meaning "A grey car" or 私の母 (わたしのはは) meaning "My mother". However, i-adjective are not nouns, we can't use の here. They can be placed anywhere a noun would be such as the topic, subject or object.

To describe nouns using an i-adjective, simply place the i-adjective before the noun, that's it:

Irregular Adjective いい

You may remember from one of our earliest lessons that いい means "Good", however, even though it is an i-adjective, it cannot be conjugated. いい is an exception where this happens.

In order to conjugate the word "good", you must use the older word よい (yoi) instead. For that reason, saying いくない (ikunai) is incorrect; it must be 良くない (yokunai). Therefor, いい (ii) should only be used alone and if you need to conjugate the word "good", you must use よい (yoi) instead.

Also, did you notice that when いい got conjugated, it actually became いく (iku) meaning "to go" and the following ない (nai) simply implying "not being".

Additional Notes