
launisch
moody
Frequently and unpredictably changing in mood, which often makes someone difficult to deal with. Also used figuratively for something that behaves inconsistently and unpredictably.
Mein Chef ist so launisch, dass er uns manchmal freundlich begrüßt und kurz darauf ohne erkennbaren Grund anschreit.
My boss is so moody that he sometimes greets us warmly and then, shortly afterward, shouts at us for no apparent reason.