内剛 ないごう Meanings Noun tough at heart Kanji 内 inside. Read as ナイ. 剛 sturdy. Read as ゴウ. Example sentences 見た目には優しそうだけど、彼って皆から外柔内剛の結構なタフネゴシエータと言われているよ。He seems like a softy on the surface, but at the core he's got an iron will that makes him an extremely tough negotiator. Words containing 内剛 外柔内剛 (がいじゅうないごう) gentle but firm 内剛外柔 (ないごうがいじゅう) gentle on the outside but tough on the inside Jinuma: Japanese Dictionary · Word lists