If you're livid, you're furious, in a black cloud of anger. The Latin root this word comes from means "bluish-gray" or "slate-colored," and you can also use livid to describe the color, such as a livid bruise or a livid sea.
Livid, even when it means "bluish-gray," has the sense of something not quite right. If the sky is livid, there's something ominous about it. Similarly, if your skin is livid, there's something wrong — you're either covered with bruises or you're at death's door, anemic and ashen. But livid is used most often to describe fury. What if you waited in line 15 hours and the person in front of you got the last seat for the hottest concert of the summer? You'd be livid!