Spleeny is a somewhat archaic term used to describe someone who is irritable, peevish, or overly sensitive. While not commonly used in modern English, there are many synonyms that can be used to convey a similar meaning. For example, someone who is spleeny might also be described as moody, touchy, or cranky. Other synonyms for spleeny include testy, querulous, fractious, and petulant. These words all describe a person who is easily annoyed or upset, often without just cause. While the word spleeny might be seen as outdated, there are certainly plenty of modern words that can be used to convey the same idea!