An archaic ku-adjective meaning 'good', 'excellent', or 'pleasant'. Found mainly in classical or literary Japanese and roughly corresponds to modern よい.
この歌はよし、と人々に評された。
This poem was praised as good by the people.
武士は主の命を受け、よしと覚悟した。
The samurai received his lord's command and steeled himself, deeming it right.