Describes something that is not complex, easy to understand, or straightforward. Also used for a person who is simple-minded or naive, often with a negative or pitying nuance.
Antonyms: 複雑
この問題は単純だからすぐ解ける。
This problem is simple, so I can solve it right away.
彼は単純な性格で、すぐ人を信じてしまう。
He has a simple-minded personality and trusts people too easily.
Actually, it's not that simple a matter.
The failure was caused by thinking about it too simplistically.
He's such a simple person that he gets pleased the moment someone flatters him.
simplicity
simple hot spring