Modifiers matching grump:

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

Simple categories matching fastidious:

• person,
• grump,
• foreigner,
• miser,
• businessman,
• gentleman,
• snob,
• psychiatrist,
• detective,