内ない剛ごう外がい柔じゅう

noun

gentle outside, tough inside; iron hand in a velvet glove

A yojijukugo describing a person who appears gentle and mild-mannered but possesses inner strength, firmness, or resolve. Often used to praise someone's character.

• 彼かれは内ない剛ごう外がい柔じゅうな人ひとで、普ふ段だんは穏おだやかだが芯しんが強つよい。

  He is a person who is gentle on the outside but tough on the inside—usually calm but with a strong core.