Open English Wordnet
Adjectives
(a)temperamentalrelating to or caused by temperament“temperamental indifference to neatness”, “temperamental peculiarities”
(s)erratic, temperamentallikely 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)