Synonyms for the word "selfimportantly" include pompously, arrogantly, haughtily, narcissistically, and conceitedly. These words all describe someone who behaves in a manner that suggests they believe themselves to be superior or more important than others. A self-important person may often boast about their achievements or position in society, and may disregard the thoughts or feelings of those around them. Some other related words include pretentiously, snobbishly, and egotistically, which all have similar connotations of arrogance or superiority. Using these synonyms can be helpful when trying to convey a certain tone or attitude in writing or conversation.