The term un-presumptuous refers to behaviour that is not arrogant, boastful, or self-important. To find the antonyms for un-presumptuous, one can look for words that express the opposite meaning. Some antonyms for un-presumptuous include arrogant, boastful, conceited, egotistic, haughty, pompous, pretentious, and self-important. These are all words that describe personality traits that are opposite to being un-presumptuous. Therefore, if one wants to avoid being un-presumptuous, they can display these antonyms instead, which usually do not lead to good social interactions but may be useful for other purposes.