Bad blood: o que significa?

You know we've been quarantined these past days because of coronavirus and like many people I've been taking the time to stay home and catch up on the many series and movies I used to ignore. It was during one of these movies I heard someone using the expression bad blood. Let me tell you what was happening when it came up.

There's this couple that's recently got into a relationship and there's this girl who used to be very close friends with the guy from the couple. There wasn't really a problem until the girlfriend found out about her boyfriend almost dating her before she became his girlfriend. It was a situation where basically he would've dated this other girl if it wasn't for a coincidence. So obviously the girlfriend got really insecure thinking about the possibility of being a second choice.

When he hears of her insecurity he approaches her in a somewhat surprised way to show how nonsense those thoughts of hers were: 'oh that's why there was all that bad blood between you two before I met you'.

Bad blood is nothing but tension and disdain between two or more people due to past disagreement or transgressions. What he meant to say to her is that he noticed some kind of animosity between them two but didn't supposedly understand why.

That expression also instantly reminds me of Taylor Swift's song entitled bad blood. Right in the beginning of the song she starts off by saying "cause baby now we've got bad blood". There was a lot of fuss over this song because soon she revealed the song was about another female artist, who according to her attempted to sabotage one of her concert tour ls by hiring the people who worked for her. So there was a lot of bad blood between them two from that point on. That's all for now guys. Take care!