Boxer Adrien Broner -- RAPPING W/ RICK ROSS ... Spits About Strip Clubs, Guns, Booze

If boxing phenom Adrien Broner is trying to make noise outside the ring -- he found the right way to do it ... teaming up with Rick Ross on a new rap that's all about spendin' cash and stripper ass.

The 24-year-old former WBC champ just dropped his new joint, "40," which includes lyrics like:

-- "Hit the club at 12:40 with like 40 on me"
-- "The watch I got, it cost me 40."
-- “Miami nightlife [King of Diamonds] man they took 40 pictures"
-- "Man there was 40 bottles of liquor and 40 strippers"
-- "Strapped at the 40/40 with two 40s on me”

Interesting timing for Broner to drop the new song, considering Floyd Mayweather just told the media he thinks Broner should spend less time rapping and more time boxing.

Fun Fact -- In 3 years, Mayweather will be 40.