Modifiers matching grump:

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

Simple categories matching mean:

• arthropod,
• predator,
• tyrant,
• equivalent,
• person,
• appliance,
• ruminant,
• thief,
• warrior,
• property,
• device,
• miser,
• emperor,
• bully,
• stuff,
• code,
• terrorist,
• conqueror,
• content,
• mammal,
• article,
• category,
• object,
• animal,
• sector,
• businessman,
• villain,
• dictator,
• grump,
• affirmation,
• thing,
• malfunction,
• characteristic,
• cat,
• data,
• thug,