Konna yaroo Share definition Flag An insult often used by the yakuza. Is similar to calling somebody a fucker, but in Japanese. It is widely considered to be the biggest insult in the Japanese language. Some lame fucker: Sorry man, I scratched your new car. Me: Konna yaroo! Konna yaroo by Johnny Rocketfingers July 18, 2003 Get the Konna yaroo mug.