Hayai, Hayai, and Osoi 速い, 早い, 遅い

Two words that show up a lot in battle anime and manga are hayai 早い, hayai 速い, and osoi 遅い... wait, what? There are three of them! Let me say it again, this time without the kanji: hayai and osoi. These words are usually related to the characters' speed, but their meanings are more than just that.

The word hayai 速い means "fast" in Japanese. It's an -i adjective, so you can say things like hayaku, hayakute, hayakatta, etc. Its antonym, osoi 遅い, means, well, it means "slow" in Japanese, of course. Except when it doesn't.

The word hayai 早い, with the 早 kanji instead of the 速 kanji, has a slightly different meaning: it means "early", and not "fast". If you go fast, you usually get there early, but one thing doesn't necessarily means the other. Like hayai 速い, the word osoi 遅い is also an antonym for it, meaning osoi can also mean "late" as well as "slow."

Vocabulary

Though the words sound equal, they are homonyms, there are differences in meaning between the two kanji, 速 and 早, so they aren't synonyms too. This is despite the two hayai being almost the same most of the time.

Here are some words with each kanji so you can tell the difference between their usage.

Hayai 速い

First, the one we already know:

• hayai 速い
  To be fast. To be quick.

Now some speed levels.

• sokudo 速度
  Speed. Speed level. How fast something is.
• kousoku 高速
  High speed.
• teisoku 低速
  Low speed.
• Speed learning.
• onsoku 音速
  Speed of sound.
• kousoku 光速
  Speed of light.

And then, some words to do things... fast.

• sokutatsu 速達
  Express delivery.
• sokketsu 速決
  Fast decision. Rash decision.
• sokudoku 速読
  Quick reading.
• sokkou 速攻
  Quick attack.
• sokkou 速効
  Quick effect.
• sokushuu 速習
  Quick learning. Intensitive learning.

Hayai 早い

Again, the word we already know:

• hayai 早い
  Early. To be early.

And then we have these adverbs withtwo hayai instead of one.

• sassoku 早速
  To do it now or soon. Let's go
• hayahaya 早々
  To do soon.

Then we have these words about the time of the day.

• souchou 早朝
  Early in the morning.
• souban 早晩
  Early or late. Morning or evening. Eventually.

And finally these about doing things early.

• hayaoki 早起き
  Wake up early.
• hayane 早寝
  Go sleep early.
• soutai 早退
  Leave early, or earlier than normal.

Osoi 遅い

First the word we already know, which has two meanings, as we already know.

• osoi 遅い
  Slow or late.

Then some antonyms for hayai 速い.

• chitatsu 遅達
  Delayed delivery. Late delivery.
• chishinji 遅進児
  Child that learns slowly.
  (literally "child that advances slowly")
• chikou 遅行
  Delayed effect. Slow effect.

Then some antonyms for hayai 早い.

• okureru 遅れる
  To be late. To delay.
• okure 遅れ
  A delay. Lag..
• osojimai 遅じまい
  To close late. (a shop, etc.)
• osoku naru 遅くなる
  To be for later. To do something later.
• chikoku 遅刻
  To be late somewhere. To get there after the right time. (school, etc.)
• tiharai 遅払い
  Late pay. Delayed pay.