na-adjective, noun
integrity; moral courage; rigidity
Describes a person of upright, unbending character; also used for rigid, unyielding things. The moral sense is more common than the physical one.
彼は剛直な人柄で、誰からも信頼されている。
He has an upright character and is trusted by everyone.
この素材は剛直で、加工が難しい。
This material is rigid and difficult to process.