The word "eventempered" is an adjective that describes a person who is even-keeled, calm, and balanced in their emotions and behavior. Some antonyms for this word can be "temperamental," "volatile," "moody," "hot-headed," "impatient," "irritable," "fickle," "unpredictable," and "erratic." A temperamental person is easily swayed by their moods and tends to overreact or be overly sensitive to situations. A volatile person is unpredictable and can easily become explosive or aggressive. Someone who is moody tends to have extreme shifts in their emotions from one moment to the next. Being hot-headed is another antonym for eventempered, indicating a person who is easily angered or frustrated.