Napalm is a jelly-like form of gasoline used in fire bombs and flamethrowers. It's a deadly, painful weapon.
Napalm sticks to skin, causing severe burns and making it one of the most horrible weapons used in combat. It was used often in the Vietnam War, and images of victims suffering from napalm burns helped make people question U.S. tactics and the war in general. These days you might hear the word napalm used to describe anything deadly or unpleasant. Spicy hot chicken wings could be like napalm on your taste buds or a touchy issue might be "political napalm."