(It's actually called taunt) I don't know the specifics as it's been a second, but basically a scenario will trigger where a guy (or girl, I just have all male on) will I think be harassing another synth and you have to choose to insult them.
I'd try socializing , finding missing synths, and going to the market to try and trigger it.
You'll see the hint on how to get it in inventory, Learned moves.
It'll force your enemy to light punch you, really good early game when you can't tank two or three heavy punches.