The word "spleenful" refers to someone who is ill-tempered, angry, or malicious in behavior. Synonyms for this word include irritable, cranky, grumpy, peevish, moody, and testy. Other words that can be used as synonyms for "spleenful" include cantankerous, crotchety, and curmudgeonly. These words all describe someone who is difficult to get along with and may be prone to outbursts of anger or frustration. It is important to choose the right synonyms when describing someone as "spleenful," as some words may have stronger connotations than others.