After confronting Eobard Thawne, the man who would go on to assume the identity of Earth-1s Harrison Wells and work alongside Cisco Ramon on a daily basis, mentoring him and even being the indirect cause of Cisco getting his powers, we see Cisco get some of his feelings off his chest as he gives a verbal beat down to Reverse-Flash. In typical Cisco style, he ends his diatribe with a Bye Felicia. Now Im not quite as down with the kids as Cisco Ramon, but I know that this phrase is a total putdown used by the youth of today. After a quick search, Urban Dictionary sums up the phrase beautifully as: When someone says that theyre leaving and you could really give two sh*ts less that they are. Their name then becomes Felicia, a random b*tch that nobody is sad to see go. Theyre real name becomes irrelevant because nobody cares what it really is. Instead, they now are Felicia. So, Cisco basically sticks it to Eobard Thawne by referring to him in a way that shows just how little he thinks of his former/future mentor (depending on timelines).