spook

This word has several common meanings. It can mean a ghost, the kind that people imagine in dark houses and old stories. It also means to frighten or startle someone or something, as when a sudden noise spooks a horse or a person in a tense moment.

It is also used for feeling nervous or uneasy: someone can be spooked by bad news or a strange event. In informal English, especially in stories about intelligence work, it can mean a spy or secret agent. In U.S. English, though, the noun has also been used as a racial slur for Black people, so that use is offensive and should be avoided. The meaning depends a lot on context: ghost, fear, unease, or secret work.

The word "spook" has a long history in English and several different meanings. It came into English from Dutch in the early 1800s and first meant a ghost or phantom, the kind of spirit people imagine in haunted places or old tales. That sense is still easy to recognize today, especially in Halloween language or in stories about haunted houses.

From there, the word also developed into a verb meaning to frighten, startle, or unsettle. A loud sound can spook a horse, a sudden movement can spook a cat, and bad news can spook investors or ordinary people. In this use, the idea is not always full panic; it often suggests a quick shock or a strong feeling of unease that changes someone's behavior.

The word is also common in the form spooked, meaning nervous, uneasy, or disturbed by something strange or worrying. Someone might feel spooked after hearing footsteps in an empty hallway, or after seeing the market fall sharply. This meaning often sits between simple surprise and deeper fear.

Another established meaning is an informal noun for a spy or secret agent, especially in political thrillers, war stories, or talk about intelligence agencies. This sense likely grew from the idea of someone moving secretly like a ghost.

There is also an important warning about usage. In U.S. English, spook has been used as a racial slur for Black people. That use is offensive. Because of that history, the noun can sound harsh or risky in some contexts, even when a speaker only means "spy." In short, the word can point to ghosts, sudden fear, nervous unease, or secret agents, but one historical use is insulting and should not be used.