Good & Bad — いい/わるい

Every い-adjective follows the same rules. Except one. The most useful one.

What You'll Learn#

New vocabulary: いい (good), わるい (bad), よくない (not good), よかった (was good), 天気 (weather), 調子 (condition)

Lesson Transcript#

The Irregular Adjective: いい#

いい looks like a normal い-adjective, but it descends from the older form よい. In the present tense, everyone says いい. But the moment you conjugate it, the よ stem returns.

The Regular Counterpart: わるい#

わるい follows every standard い-adjective rule. No surprises, no ghosts.

Practice Sentences#

Conjugation Comparison#

Cultural Note: よかった#

よかった literally means "it was good," but Japanese speakers use it as an exclamation of relief — like "thank goodness" or "what a relief." You barely caught the train? よかった. Your friend finally answered their phone? よかった. It is one of the most human words in the language.