Okay kiddo, do you know what soldiers are? They are people who fight in wars to protect their country. When soldiers fight, they need to move around quickly to avoid getting hurt.
Now, a tirailleur is a special kind of soldier. They are really good at moving quickly and quietly through places where there might be dangers like enemies or traps. They are like the scouts of the army.
Tirailleurs were originally soldiers from Africa or the West Indies who served in the French army. They were known for their bravery and skills in battle. Today, the term can refer to any soldier in any army who is good at moving quickly and quietly.
So, if you ever need someone to sneak around and find out what the bad guys are up to, you might want to look for a tirailleur. They are a really important part of any army!