barricade
A quickly built barrier that blocks people or things.
A barricade is a hastily built barrier used to block a path or protect people from danger. Picture protesters quickly stacking furniture, boxes, or wooden planks across a street to prevent police from advancing. Or imagine store owners boarding up their windows with plywood before a hurricane arrives. That's a barricade: something thrown together fast to create a wall where none existed before.
The word comes from French, where barrique means barrel. During uprisings in Paris centuries ago, citizens would roll heavy barrels into the streets and pile them high to create defensive walls. Today, police might set up barricades of metal fences or concrete blocks to control crowds at parades or protests. Construction workers use barricades to keep pedestrians away from dangerous work zones.
Unlike permanent structures like walls or fences, barricades are temporary and practical. They're meant to work right now, not to last forever. You can also use barricade as a verb: if someone tries to break into a room, you might barricade the door by shoving a heavy desk against it. During a school lockdown drill, students learn to barricade classroom doors to stay safe. The key idea is creating a quick obstacle that makes it harder for someone or something to get through.