“to die / to perish” in Japanese is 亡, read bou, mou, na (ぼう, もう, な). It is a Grade 6 Kyōiku kanji, taught in year 6 of Japanese elementary school, and appears in words such as 死亡 (death).
What does 亡 mean?
祖父が亡くなる。
Same sound, different character — the classic trap. Compare them side by side: