Synonyms for Temperamental (same or very similar meaning)
WordNet sense 1 (subject to sharply varying moods):
moodyWordNet sense 2 (of more than usual emotion):
emotionalWordNet sense 3 (likely to perform unpredictably):
erraticWordNet sense 4 (not worthy of reliance or trust):
undependable, unreliableFrom the ODE community, based on WordNetadd/edit