It is a word that is used for countering the "Who? no, who asked" argument it can be used after "Who?" or even after the "who asked" but it can be used in any scenario.
"DOKTOR, TURN OFF MY BOOWOMP INHIBITOR"
Doctor: "Right away sir turning on your w-what now?"
"You know, that sound in SpongeBob when someone is sad? Booooowomp."
Better known as the Low Bork, a Hanna-Barbera sound effect. The sound has been featured in SpongeBob, which usually plays when they're sad.
SpongeBob: I guess I'll have to move back with my mom and dad. shown a picture of SpongeBob's parents smiling
Patrick: No, wait a minute, no you don't. BOO-WOMP! shown picture of SpongeBob's parents frowning We can build you a new house!