If you are incensed, you are very, very angry — not a little annoyed, but burning with it. That burning idea is the old heart of the word: the verb incense means to make someone furious, from Latin about setting something on fire. Though actually, English also has incense as a noun: the sweet smoke burned in temples and churches. Historically they share that ‘set on fire’ story, but in real life they feel like two different words, and incensed in ordinary reading almost always means ‘furious.’ It is a strong, slightly literary word; everyday talk more often says furious, livid, or just very angry. You will see incensed by, incensed at, and incensed that.