毅 in Chinese / Japanese...

毅 is the simplest way to express perseverance in Chinese and Korean Hanja.
This single-character version leaves a bit of mystery about what kind of perseverance you might want to convey.

In Korean, this is usually associated with “strength of character.”

In Japanese, this character can be pronounced in a dozen different ways (so we have left out the Japanese pronunciation guide that normally appears above). In Japanese, this Kanji would usually be translated as “strong” (perhaps strong-willed).

堅毅 means unswerving determination or firm and persistent in Chinese.

This single Chinese word means “firm and persistent” and/or “unswerving determination.”

剛毅 is a Japanese and Chinese word that means resolute and firm, fortitude, firmness of character, hardihood, manliness, or macho.

毅力 is a way to express “perseverance” with the idea of “willpower” in Chinese and old Korean Hanja. It can also mean “strong-willed.”

The first character means “strong” and “persistent,” while the second means “strength” and “power.”

The first two characters mean resolute with firm determination.
The second two characters mean reliable.

Together, this creates a 4-character expression that means dependable.