Ill temper is a phrase used to describe someone who is in a bad mood or easily irritated. There are several synonyms that can be used to describe someone with this behavior. One such term is "bad-tempered," which implies that someone is easily annoyed and often argumentative. Another word that can be used is "cranky," which suggests that someone is irritable and easily frustrated. "Sour" is another synonym for ill temper and is often used when someone is in a persistent bad mood. Finally, the term "peevish" is another synonym for ill temper that suggests that someone is easily annoyed or vexed by minor issues.