ろうすい 老衰 Common word JLPT N1 Wanikani level 49 Play audio LinksSentence search for 老衰Sentence search for ろうすいKanji details for 老 and 衰Edit in JMdict Noun, Suru verb, Intransitive verb, Noun which may take the genitive case particle 'no'1. senility; senile decay; infirmity (through age) Discussions Log in to talk about this word.