Kevin Durant is fighting back against a lawsuit claiming he stole the nickname "Durantula" from a 1980s musician ... arguing that he didn't give himself the moniker and doesn't even use it to make money.

As TMZ first reported, the Oklahoma City Thunder star was sued by guitarist Mark Durante, who claimed he had trademarked the name and used it to sell merchandise long before KD came along.

But in his response -- filed earlier this month in Illinois Federal Court -- Durant claims the media and his fans have been calling him by the name his whole career. Durant says he has NEVER used the name to sell merchandise ... so Durante's lawsuit has no merit.

In addition, Durant claims that no one would ever confuse him with Durante (who has played with the likes of Public Enemy, The Aliens and The Next Big Thing).

KD wants the lawsuit tossed completely and wants Durante to cover his legal fees.

A judge has yet to rule.

Hoops superstar Kevin Durant is one game away from losing the NBA Finals, and now one lawsuit away from losing his famous nickname -- "Durantula" -- because a guitarist claims KD jacked it from him.

Durant was sued today in Federal Court by a guy named Mark Durante -- a guitarist who, according to the lawsuit, was a big deal in the 80s ... playing with Public Enemy, The Aliens, The Next Big Thing, and (our favorite) The Revolting Cocks.

TMZ obtained a copy of the lawsuit, in which Durante says he adopted the name "Durantula" for his "on-stage and performance persona" -- and has used it to market "music, recordings, apparel, t-shirts, guitars, and related merchandise."

Meanwhile, sports fans have adopted the handle for the Oklahoma City Thunder star and current NBA scoring champ.

Durante claims he sent KD's people a couple letters "demanding they stop using the nickname" -- but says Durant's reps claimed he wasn't using it.

In the suit though, Durante claims Nike has used the moniker to launch a shoe campaign -- and KD himself signed "Durantula" on basketballs that are for sale through his website.

The guitarist says he registered the "Durantula" trademark. He's suing for damages and an injunction stopping KD from using the name.

Calls to Nike and Durant's reps weren't immediately returned.