内柔外剛 ないじゅうがいごう Meanings Noun tough on the outside but soft at heart Kanji 内 inside. Read as ナイ. 柔 soft. Read as ジュウ. 外 outside. Read as ガイ. 剛 sturdy. Read as ゴウ. Word lists Yojijukugo (四字熟語) Jinuma: Japanese Dictionary · Word lists