11 Adjectives—Tense,Past tense, Non-past tense

Introduction to Adjectives

Adjectives describe the state or nature of a person or thing; they also express feelings, emotions, and value judgments. In Japanese, there are adjectives and adjectival nouns used to describe the state or nature of a person or thing. Both function similarly, but their grammatical transformations differ, which needs attention.

Characteristics of Adjectives and Adjectival Nouns

Each word has a stem and a suffix, and the main characteristic of adjectives is that their suffix is "い". This does not mean that any word ending in "い" is an adjective. Let's compare two words to understand this better.

Adjective: 暑い (atsui) Adjectival Noun: 嫌い (kirai)

Dictionary Form	Part of Speech	Stem	Suffix
暑い	Adjective	暑	い
嫌い	Adjectival Noun	嫌い	だ

From the table, we can see that the suffix of the adjective "暑い" is "い", while the suffix of the adjectival noun "嫌い" is "だ". The suffix "だ" of adjectival nouns does not appear in the dictionary form, so it cannot be seen when looking up the word in a dictionary. If we only look at the dictionary forms "暑い" and "嫌い", we notice that both end with "い", which can easily confuse beginners, leading them to mistake adjectival nouns ending in "い" for adjectives. This can cause problems when making grammatical transformations. However, there are few adjectival nouns that are easily confused, so there is no need to worry too much; just pay a little extra attention when memorizing these words.

Dictionary Form: The term "dictionary form" comes from the Japanese "辞書" (jisho), meaning dictionary. Since only the base form can be found in the dictionary (transformed forms will not appear in the dictionary), the base form is also called the dictionary form.

How to Determine Adjectives and Adjectival Nouns

Generally, you can determine from the grammatical changes in the context. It is not possible to know just by looking at the word itself, so please be diligent in looking up words in the dictionary. As mentioned earlier, there are few adjectival nouns that are easily confused, so you can memorize them separately. Below are some common examples for beginners. (For more adjectives, please refer to the N5 vocabulary list for adjectives.)

Adjectives: 暑い (atsui), 寒い (samui), 広い (hiroi), 狭い (semai), 高い (takai), 低い (hikui), 長い (nagai), 短い (mijikai), 美味しい (oishii), 美しい (utsukushii), etc.

Adjectival Nouns: 賑やか (nigiyaka), 静か (shizuka), 上手 (jouzu), 下手 (heta), 立派 (rippa), 大切 (taisetsu), 便利 (benri), 好き (suki), 嫌い (kirai), きれい (kirei), etc.

From the examples above, we can see that adjectives with the suffix "い" are easy to recognize. Adjectival nouns that are easily confused include "嫌い" and "きれい". Their stems are "嫌い" and "きれい" respectively, and their suffix is "だ" (which is not seen in the dictionary form), so just memorize these words separately. Only common examples are listed above; if you encounter unknown words that you are unsure are adjectives or adjectival nouns, please be diligent in looking them up in the dictionary.

When followed by a noun, the suffix for adjectives is "い", while the suffix for adjectival nouns is "な". Therefore, adjectives are also called "い-adjectives" (often noted as A), and adjectival nouns are called "な-adjectives" (often noted as Na).

Adjective Tenses and Forms

Example Sentences:

今日は暑いです。 It is hot today. 今日は寒くないです。 It is not cold today. 昨日は寒かったです。 It was cold yesterday.

Below is a tense analysis using "暑い" (hot):

Tense	Form	Polite Form	Plain Form
Non-past	Affirmative	暑いです。 It is hot.	暑い。 It is hot.
	Negative	暑くないです。 It is not hot.	暑くない。 It is not hot.
Past	Affirmative	昨日は暑かったです。 It was hot yesterday.	昨日は暑かった。 It was hot yesterday.
	Negative	昨日は暑くなかったです。 It was not hot yesterday.	昨日は暑くなかった。 It was not hot yesterday.

From the table above, we can deduce:

• An adjective without "です" is in plain form, while an adjective with "です" is in polite form.
• For negative sentences, remove the final "い" from the adjective and add "く", followed by the negative "ない".
• For past tense, remove the final "い" and add "かった".
• For negative past tense, remove the final "い", add "く", followed by the negative "ない". Note that "ない" itself is an adjective, so its past tense also requires removing the final "い" and adding "かった", resulting in "くなかった".

There are two ways to express the polite negative form:

	Negative Form ①	Negative Form ②
Non-past tense	暑くないです。	暑くなかったです。
Past tense	暑くなかったです。	暑くありませんでした。

Both Negative Form ① and Negative Form ② have the same meaning. "～くありません" (～ ku arimasen) is more formal and polite, while "～くないです" (～ ku nai desu) is more colloquial.