It could mean that there is a fan - created story (fanfic) about Naruto where the characters are depicted in a 'gangsta' - like style. For example, they might have the attitude, appearance, or behavior associated with gangsters in a modern or unique setting within the Naruto universe.
Probably not as popular as the more traditional Naruto fanfics. The Naruto series has a large following for its original ninja - based story, and the 'gangsta' theme might be a bit too far - fetched for some fans.
Another theme is brotherhood or comradeship within a more 'gang - like' setting. Characters come together not just as a ninja team but as a group with a shared ideology, like a gang. They protect each other and fight for their own beliefs, which might be different from the village's official stance. This can be seen in fanfics where Naruto and his friends form a sort of underground group to support those who are oppressed by the system.
Well, one interesting concept could be the re - imagining of Naruto characters in a more 'gangsta' - like urban setting. For example, Naruto might be a street - smart kid growing up in a tough neighborhood, using his ninja skills in a different way to survive. Another concept could be the portrayal of the different ninja clans as rival gangs, with their own territories and codes of conduct.
Typically, Naruto in a 'gangsta naruto fanfic' is a tough and street - wise character. He's not the naive kid we see in the original. He has a bit of an edge, using his natural exuberance and ninja skills to navigate the rough world he's in. Sasuke might be a brooding, more mysterious figure, perhaps with his own hidden motives within the 'gangsta' setting.
One popular 'naruto gangsta fanfic' could be 'Naruto: Street Shinobi'. It portrays Naruto in a more edgy, street - smart kind of role, dealing with the underbelly of the ninja world in a unique way.