Spleened is a unique word that implies anger or being in a bad mood. While there are very few synonyms for this particular word, there are many other words that can convey a similar sentiment. For example, words like irate, livid, furious, outraged, or incensed give off a feeling of anger or frustration. Another set of synonyms that can be used instead of spleened are cranky, grumpy, irritable, grouchy, moody, and cantankerous. Although synonyms for spleened may not be as straightforward to find, with a little bit of research one can discover a diverse range of words that can capture the same emotions.