Other forms: irefully
Use the adjective ireful to describe someone who's furious. You'll probably be ireful when you realize that your little brother used your favorite dress shirt as an apron when he baked brownies.
The word ireful is an uncommon, old-fashioned way to say "really angry." You may tend to be an ireful driver, yelling and gesturing at other cars, or you might write an ireful letter to the editor of a newspaper after reading a badly reported, inaccurate story. When you're ireful, you're full of ire, which comes from Latin and means "wrath, anger, rage, or passion."