To terrorize means to deliberately frighten someone so badly and so repeatedly that they live in constant fear. A bully who terrorizes other students creates an atmosphere where their victims feel afraid all the time, never knowing when the next threat or attack will come.

When someone terrorizes others, they make fear a constant presence in their victims' lives. A mean older sibling might terrorize a younger one by threatening them every day, or a gang might terrorize a neighborhood through intimidation.

Historical examples show how powerful groups have used terror to control people: dictators have terrorized entire populations to maintain power.

The word can also be used more lightly: a mischievous cat might terrorize the family dog by ambushing it around corners, though of course this isn't the same as true terrorizing. When someone says their little brother terrorizes their room, they usually mean he makes a huge mess, not that he creates real fear.