Unassumingness refers to the state or quality of being modest, unpretentious, or simple in nature. However, its antonyms include arrogance, pompousness, conceitedness, pretentiousness, and ostentatiousness. Arrogance denotes a sense of exaggerated self-importance and superiority, while pretentiousness refers to the act of portraying oneself as more cultured, wealthy, or important than one really is. Pompousness implies an inflated sense of one's worth and status, while ostentatiousness involves showing off one's wealth or possessions in a boastful or flashy manner. Hence, these antonyms emphasize the opposite of unassumingness, highlighting behaviors and attitudes that are characterized by vanity, self-centeredness, and ostentation.