temperamental

Universal Words adjective 1 (usually disapproving) having a tendency to become angry, excited or upset easily, and to behave in an unreasonable way: You never know what to expect with her. She's so temperamental. * (figurative) The printer's being temperamental this morning. * He's a temperamental player (= he plays well or badly according to his mood). 2 connected with sb's nature and personality: They are firm friends in spite of temperamental differences. temperamentally adverb: I'm temperamentally unsuited to this job.