Doom means a terrible fate or destiny that seems inevitable, especially one involving destruction or death. When ancient prophecies spoke of doom, they warned of disasters that appeared impossible to prevent. When a castle's defenders knew their doom was near, they understood defeat was coming no matter how bravely they fought.

The word carries a sense of finality and heaviness. If someone predicts doom and gloom, they're forecasting disaster and despair. A fortress might be doomed to fall, or a ship might be doomed to sink. The feeling captures both that something bad will happen and that it's unavoidable, like watching storm clouds gather when you're miles from shelter.

In everyday speech, people sometimes use doomed more lightly: “I'm doomed!” a student might say when realizing they forgot about tomorrow's presentation. This exaggerates the situation for effect, since forgetting homework isn't actual doom.

The word also appears as a verb: to doom something means to destine it for destruction or failure. Bad planning might doom a project before it even starts.