expression, ichidan verb
displease; offend; hurt someone's feelings
Used when someone's mood is spoiled or they become upset, often because of something said or done. The subject is typically the person or action that causes the displeasure.
彼の冗談が彼女の機嫌を損ねた。
His joke offended her.
そんなことを言うと、上司の機嫌を損ねるよ。
If you say something like that, you'll hurt the boss's feelings.