A matter that causes worry or distress; a problem or concern someone is troubled by.
友達に悩み事を打ち明けた。
I confided my worries to a friend.
親に相談したら、悩み事が少し楽になった。
After talking it over with my parents, my worries eased a little.
仕事の悩み事で夜よく眠れない。
I can't sleep well at night because of worries about work.