Dictionary / Vocabulary / 唯我独尊
ゆいがどくそん
throughout heaven and earth, I alone am the honored one; self-conceit; self-centeredness; vainglory
本人は唯我独尊を決め込んでいるようだけども、周りから見れば単なるわがままだよね。
He's completely convinced of his own greatness but to the people around him he's just a selfish jerk.