ようじんけんご 用心堅固 LinksSentence search for 用心堅固Sentence search for ようじんけんごKanji details for 用, 心, 堅 and 固Edit in JMdict Noun, Na-adjective (keiyodoshi)1. very cautious (watchful, vigilant); taking every possible precaution Discussions Log in to talk about this word.