Okay kiddo, so a long time ago in Yugoslavia there was a group of people called the Partisans. They were fighting against some bad guys called the Nazis who were trying to take over their country and do bad things to the people who lived there.
Now, the Partisans had a special group of people called the Bombaši. These were the really brave people who would sneak up on the Nazis and use bombs to blow up their trucks and planes and things like that. They were called Bombaši because they were really good at making and using bombs.
The Bombaši would have to be very sneaky and careful when they did their jobs. They would hide in the bushes or in buildings and wait for the right moment to strike. They were very brave because they knew that if they got caught, the Nazis would do very bad things to them.
But the Bombaši were very important to the Partisans because they helped to slow down the Nazis and make it harder for them to win the war. They were the secret weapon that helped the Partisans to fight back and eventually win their freedom.
So that's what the Bombaši were, kiddo. They were a group of brave people who helped to fight against the bad guys and keep their country safe.