noun: (uncountable) An amorphous group of right-wing ideologies opposed to multiculturalism and egalitarianism by race and sex, mostly active on the Internet; often supportive of anti-Semitism, Islamophobia, homophobia, transphobia, white nationalism and white supremacy, adherence to which is sometimes claimed to be ironic.
noun: (countable, rare) A member of the alt-right; an alt-righter.
adjective: Of or pertaining to the alt-right.
noun: Alternative form of alt-right [(uncountable) An amorphous group of right-wing ideologies opposed to multiculturalism and egalitarianism by race and sex, mostly active on the Internet; often supportive of anti-Semitism, Islamophobia, homophobia, transphobia, white nationalism and white supremacy, adherence to which is sometimes claimed to be ironic.]