intense and profound fear
"The sudden creak of the floorboard sent a wave of horror through me as I realized someone was hiding in the walls."
something that inspires horror; something horrible
"the painting that others found so beautiful was a horror to him"
intense aversion
"The smell of rotten eggs caused an immediate horror in her stomach, making her rush out of the kitchen without finishing her meal."
An intense distressing emotion of fear or repugnance.
"The sudden scream from the dark alley sent a wave of pure horror through everyone on the street."
In plain English: Horror is an intense feeling of fear, shock, or disgust when you see something terrible or frightening.
"She watched the movie with horror as the killer chased the victim through the dark forest."
Usage: Use horror to describe an overwhelming feeling of fear, shock, or disgust in response to something terrible or repulsive. It is often used with the preposition "at" when reacting to a specific event or sight, such as being horrified at a gruesome scene.
The word "horror" entered Middle English from the Old French horrour, which was borrowed from Latin to describe a physical reaction of bristling or trembling with fear. It eventually replaced the native Old English term ōga when used to express terror.