godan verb (-ru), intransitive verb
be conceited; think highly of oneself
Rare intransitive verb meaning to act self-important or put on airs. Similar to 偉ぶる (えらぶる), which is more common.
See also: 偉ぶる
彼は少し成功しただけで偉がっている。
He's acting conceited just because he had a little success.
That person always talks in a self-important way, so people dislike him.