megalomania; egomania; delusions of grandeur

extravagantly conceited; full of oneself; behaving in a way that is both overbearing and extremely proud

to think of oneself as terrific and look down on others; self-important; conceited

Literally 'Yelang thinks highly of itself'; refers to someone who is ignorant of the wider world and thinks too much of their own importance.

to be conceited and full of oneself; to become swollen with pride

arrogant and self-aggrandizing; having an inflated sense of one's own importance