Street voices
"Killing it is another way to say that you are nailing something, that you are just doing it perfectly and no one could do it better. So for instance, an example would be an inner thought you might have while you're doing really well at a job interview. Oh my God, I'm going to get this job. I am killing it right now."
What it means
Doing something exceptionally well, nailing it completely.
Usage examples
"I was killin' it at the interview, so I'm pretty sure I got the job."
"%s was killin' it on stage tonight, the crowd went wild!"
"You've been killin' it at work lately, keep it up!"