Modifiers matching grump:

• gruff,
• covetous,
• grouchy,
• rich,
• arrogant,
• penny-pinching,
• jealous,
• fastidious,
• wealthy,
• principled,
• impatient,
• ill-tempered,
• grizzled,
• condescending,
• miserly,
• heartless,
• misanthropic,
• greedy,
• mean,

Simple categories matching grouchy:

• grump,
• poet,
• person,
• singer,
• composer,
• musician,
• malcontent,