Wiz Khalifa -- Busted for Weed ... at a Holiday Inn

"Black and Yellow" rapper Wiz Khalifa tried to hide a bag of weed in his room at a Holiday Inn in Nashville ... this according to law enforcement.

According to the police report, obtained by TMZ, Metro Nashville Police responded to Wiz's room on April 21 after someone complained about a strong odor of marijuana.

When officers arrived to the scene, Wiz -- real name Cameron Jibril Thomaz -- allegedly tossed a "marijuana cigarette" out of the window.

Cops say the recovered the item ... saying, "inside the rolling paper was a green leafy substance consistent with marijuana."

According to the report, Wiz eventually admitted the joint was his and said he had 3.7 grams of weed in his pocket.

Wiz -- who's VERY open about his marijuana use -- was hit with a citation ... and probably smoked more weed after the officers left.