2.4.2. What is an i adjective?

I adjectives are Japanese words like atsui (熱い), "hot", or akai (赤い), "red", which can be conjugated like verbs and act as either adjectives or adverbs. They are called i adjectives because their plain form ends in "i". I adjectives can also come at the end of sentences, like verbs, and some linguists describe them as a kind of verb.

I adjectives also conjugate. For example, they can be negative, as in atsukunai, "it's not hot", or they can have a past tense, like atsukatta, "it was hot". They can also turn into adverbs by changing the i into a ku, hence atsuku moete iru "It's burning hotly".

Here are some examples:

Adjective (rōmaji)	Adjective (kanji/kana)	Meaning	Example
akai	あかい	red	akai kuruma "A red car"
kowai	こわい	scary	kowai eiga "A scary movie"
muzukashii	むずかしい	difficult	muzukashii mondai "A difficult problem"
atarashii	あたらしい	new	atarashii zubon "New trousers"
furui	ふるい	old	furui tatemono "An old building"
kawaii	かわいい	cute	kawaii akachan "A cute baby"

All i adjectives end in ai, ii, ui or oi. There are none ending in ei. Not all words ending in i are i adjectives. Kirai, "dislike", for example, is a na adjective, so it forms a positive as kirai da and negative as kirai ja nai. Some words can be both i adjectives and na adjectives, such as ōkii and ōki na.

Many i adjectives end in shii, particularly adjectives related to human emotions such as tanoshii (楽しい), "enjoyable", kanashii (悲しい), "sad", or muzukashii (難しい), "difficult".

Confusion may be caused when an i adjective takes the sou ending: see 2.2.1. What are the uses of the sou ending?.

Acknowledgements

This entry was partly created by Paul Blay when it was part of the "wiki sci.lang.japan FAQ".

sci.lang.japan FAQ / 2. Grammar / 2.4. Other grammar questions

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