The phrase 'assertion of superiority' is correct and can be used in written English.
You can use this phrase to refer to an expression of one's feeling of being superior or ahead of others. For example, "The CEO's assertion of superiority was evident in the way he addressed the staff."
Yet underlying the mystique surrounding their shared leadership is an unproven assertion of superiority.
At first, the sight of their younger sister, Shaylee, walking freely past the girls, struck me as painful, a constant reminder of their own constraints, her liberty a moment-by-moment assertion of superiority.
Rankism is an assertion of superiority.
As a black man with unrepentant masculinity and confident assertion of superiority, Johnson embodied the fear of White America.
It is crucial, therefore, to avoid explicit or implicit assertions of superiority.
They have not hesitated to betray me through assertions of superiority intended to hurt my human rights and my human dignity.
In Japan, certain retroactive constructions of identity and reactive counter-assertions of superiority have taken the form of what is called nihonjin-ron: theories of "Japaneseness" or "Japanese uniqueness" (see Dale 1986).
For all their witty brilliance, the sense of proselytisation in these essays is insistent - almost, in its elegant way, militant - and the Nietzschean assertion of the superiority of the artist over all creation is on the brink of being overwrought.
Nobody thinks that's a viable position nowadays, but the same impulses -- an assertion of moral superiority, an unwillingness to consider alternative points of view -- lie behind America's new spirit of unilateralism.
Slavoj Zizek's assertion of atheist superiority is based on his idea that atheists, unlike fundamentalists, do good deeds because it is morally correct, and not in order to attain God's favor.
Mr. Berlusconi's center-right coalition has been in power only about six months but he has already been in a number of scrapes with his partners in the European Union, which disapproved of his assertion of Western superiority over Islam and were angered by his decision to freeze plans to join a pan-European military defense project.
