temperamental -- (relating to or caused by temperament; "temperamental indifference to neatness"; "temperamental peculiarities")
moody, temperamental -- (subject to sharply varying moods; "a temperamental opera singer")
erratic, temperamental -- (likely to perform unpredictably; "erratic winds are the bane of a sailor"; "a temperamental motor; sometimes it would start and sometimes it wouldn't"; "that beautiful but temperamental instrument the flute"- Osbert Lancaster)
(Sound)
