堅牢堅固 けんろうけんご Meanings Noun, な-adjective firm and solid; stout and durable Kanji 堅 firm. Read as ケン. 牢 prison; jail; hardness. Read as ロウ. 固 solid. Read as コ. Word lists Yojijukugo (四字熟語) Jinuma: Japanese Dictionary · Word lists