Which word describes a person who is often moody or difficult to please?

The term that most accurately describes a person who is often moody or difficult to please is "querulous." This word specifically refers to someone who tends to complain frequently or expresses dissatisfaction, often in a whiny or petulant manner. A querulous person is not just voicing general dissatisfaction; they frequently exhibit a tendency to be irritable or argumentative, which aligns well with the notion of being moody and hard to please.

In contrast, "sanguine" suggests a cheerful and hopeful disposition, which does not fit the description of being moody. "Complaining," while relevant, is more of an action than a descriptor of a person's character traits. Lastly, "jovial" describes someone who is cheerful and friendly, which is the opposite of being moody or difficult. Thus, "querulous" stands out as the most appropriate choice in the context of the question.