assiduously
🇺🇸
/əˈsɪdʒuəsli/
🇬🇧
/əˈsɪdʒuəsli/
working very hard and carefully
He worked assiduously to earn the money for his son’s education.
彼は息子への教育のためにお金を稼ぐために一生懸命働いた。