今日の英語：add insult to injury

= 追い打ちをかける。

(idiomatic) To further a loss with mockery or indignity; to worsen an unfavourable situation. 

add insult to injury - Wiktionary

今までずっと"add salt to injury"だと思っていた。というか、

(idiomatic) To make an injury, physical or emotional, feel worse.

rub salt in the wound - Wiktionary

これと混同していた。なので気になって違いを調べたら、

Basically, "add insult to injury" is just a general statement. On the other hand, "rub it in" is a specific action done by someone. Usually, you wouldn't say a specific *person* "added insult to injury" - it just refers to when a bad situation gets even worse due to something.
But "rub it in" is *always* done by a person.

What is the difference between "add insult to injury " and "rub it in " ? "add insult to injury " vs "rub it in " ? | HiNative

 なるほど。前者は一般的な状況悪化、後者の主語は人に限られて故意に相手を痛めつける時限定。