What word describes someone who is sullen and ill-tempered?

The term that best describes someone who is sullen and ill-tempered is "morose." This word conveys a sense of gloominess and a disposition that is often characterized by being withdrawn or brooding. A morose individual typically displays a lack of enthusiasm and can appear sulky, which aligns closely with the definition of being sullen and ill-tempered.

In contrast, choices such as "eccentric" refer to someone who behaves in unconventional ways, which does not necessarily imply a gloomy or ill-tempered attitude. "Meticulous" describes a person who is very careful and precise, often regarding details, but this does not relate to temperament. "Indifferent" indicates a lack of interest, concern, or sympathy, which again does not capture the negative emotional state implied by being sullen or ill-tempered. Therefore, "morose" is the most fitting description of the individual in question, as it encapsulates both the mood and the temperament associated with such feelings.