金きん城じょう鉄てっ壁ぺきMeaningsNoun1. impregnable castle (walls) (Yojijukugo)No-adjective2. impregnable; invulnerable; unassailable (Yojijukugo)Kanji used金gold城castle鉄iron壁wallPitch accentきんじょうてっぺきComposed of金きん城じょうimpregnable castle; inner castle citadel; golden castle (nickname for Nagoya Castle)Noun鉄てっ壁ぺきiron wall; impregnable fortress; impregnable; invulnerable; unassailable; cast-ironNoun