To repel means to push something away or drive it back. When you spray bug repellent on your skin, it repels mosquitoes by creating a smell or taste they want to avoid. A raincoat repels water, making droplets bead up and roll off instead of soaking through the fabric.

In science, magnets demonstrate repulsion perfectly: try pushing two north poles together and you'll feel them repel each other, as if there's an invisible force keeping them apart. The same magnetic poles always repel, while opposite poles attract.

The word also describes driving back an enemy or attack. An army might repel invaders at the border, forcing them to retreat. A castle's thick walls helped defenders repel sieges. When you repel an attack, you successfully defend against it and push it back.

People can repel others too, though usually not on purpose. If someone has terrible manners or acts cruelly, their behavior might repel potential friends. Something repellent (notice the different spelling) is so disgusting or offensive that it pushes people away. The idea of eating spoiled food is repellent to most people.

The opposite of repel is attract: magnets either repel or attract each other, and people are either drawn to someone or repelled by them.