rap style generally credited to West Philly hip hop artist Schoolly D, but his "Gangster Boogie" (1984) used the conventional spelling; NWA was spelling it gangsta by 1988.
Examples from the Web for gangsta
And then, that “gangsta” style is just one, and less dominant than it once was.Americans Have Never Loved Poetry More—But They Call It Rap
June 29, 2014
Tupac did indeed find prison so harrowing that he soon reconsidered his gangsta ways.Tupac and Murray Kempton: The Godfather Who Wore Tweed
June 22, 2014
Every time the question of black teenagers comes up, someone blames 'gangsta rap' for their problems.Bill O’Reilly to Blacks: Stop Listening to ‘Gangsta’ Music!
February 28, 2014
Rihanna reckons that Princess Diana was gangsta—when it came to clothing, at least.Rihanna On Diana
October 2, 2013
From Jane Eyre to The Iliad, literature gets a gangsta makeover in this viral rap video titled “B*tches in Bookshops.”Olbermann on ‘Letterman,’ Palin on ‘Today’ Show, and More Viral Videos
The Daily Beast Video
April 7, 2012