IED

Improvised Explosive Device.
Often referring to makeshift bombs or explosives made from common items.
Usually used when no real explosives are nearby, and one is required.
ex: A Molotov Cocktail, or a C4.

"This door is blocked off from the inside, and we need to get in. What now?"
"I found some gunpowder earlier, maybe we can make an IED.
"Great, this door will definitely go down then."