Splenetic is an adjective that means ill-tempered or spiteful.
Our word of the day shares its origin with the word spleen, an abdominal organ that serves as part of the immune system. The Ancient Greeks believed the spleen was the seat of a bad temper, so the word splen (splan) meant ‘ill-tempered.’ Centuries later, splenetic entered English as an adjective for spiteful or malevolent.
After working with some ill-tempered people, I became something of an expert at recognizing splenetic behavior. Most importantly, I became good at not hiring such people.