Blaccent, the words "black" and "accent" mixed, is the offensive imitation of Black Vernacular English by non-black people.
Awkwafina, Iggy Izalia, and other popular celebrities often use a blaccent to profit off of and rise to fame by appearing cooler or more hip. It's appropriation of black vernacular, much akin to the appropriation of AAVE (African American Vernacular English) in pop-culture.
Its a term used to describe NBP = Non Black people who appropriate Black culture wrongly by speaking in a monolithic Blaccent while appropriating AAVE = African American Vernacular English.