Repel and repulse overlap closely: both can mean to drive back an attack, and both can mean to cause disgust. The main practical difference is range — repel also covers keeping something away by physical or chemical force, like a spray that repels insects, a use repulse doesn't share. Repulse is also the more natural choice as a noun for the act of driving something back.
The core difference
The two verbs largely overlap; repel additionally covers keeping things away by physical or chemical force.
- repel — drive back an attack, keep something away by force, or cause dislike: This spray helps repel mosquitoes.
- repulse — drive back an attack, or cause strong disgust: The defenders repulsed three waves of assault before nightfall.
How to tell them apart
Both words trace back to the same Latin verb, repellere, "to drive back", which is why their meanings sit so close together. In military and disgust senses they're often interchangeable: an army can repel or repulse an invasion, and a smell can repel or repulse someone.
Where they part ways is everyday physical repelling — a coat that repels rain, a spray that repels insects — which only works with repel. Repulse also works as a noun for the act of driving something back, as in "a decisive repulse of the enemy forces", a use repel doesn't share.
