If your moods change quickly and dramatically, people might describe you as temperamental. If you weren't so temperamental, maybe your friends would open up to you more. Did I say something wrong?
The adjective temperamental can also be uses to describe objects that behave unpredictably. A temperamental air conditioner can make for a long, hot summer. Fortunately, you're not temperamental or you might have smashed it to bits by now. The second “e” in temperamental gets swallowed so that it sounds like "temp-ra-MENT-al" (four syllables).
