キャラクター

Samurai Skills Description 4.0 Japanese Background
https://jp.finalfantasyxiv.com/lodestone/character/1912534/blog/3373509/

Samurai Skills Description 5.0 Japanese Background
https://jp.finalfantasyxiv.com/lodestone/character/1912534/blog/4112918/

Samurai Skills Description 6.0 Japanese Background
https://jp.finalfantasyxiv.com/lodestone/character/1912534/blog/4865383/

Also please refer to https://www.reddit.com/r/ffxiv/comments/i2cabf/sam_untranslated_cultural_notes/

天眼通 Tengetsu
Buddhist term. The power to freely see through events that ordinary people cannot see.
天眼 means the eye that can see everything.

暁風 Gyofu
暁 means "dawn".
暁風 means "wind that blows from north to north-east during spring and summer along the coast of the Sea of Japan", as DeepL says.
(I was surprised to see this long translation in just "暁風".)

残心 Zanshin
In the martial arts, it refers to the mental posture that maintains tension even after completing a single action. In kendo, it refers to the mental posture of preparing for the opponent's counterattack after a strike.

天道 Tendo
天道 has several meanings.
In Buddhist term, it means the collective name for the world of greed(欲界), color(色界), and colorlessness(無色界). Please refer to https://en.wikipedia.org/wiki/Trailokya (三界).

In simple(?) meaning, 天道 means the natural reason for nature. The way of natural nature. The way of heaven. Heavenly reason.