Lamar Odom Cracked Out Rap Video -- I Cheated on Khloe Kardashian

Lamar Odom's drug problem is only getting worse -- at least that's how it looks in this video, shot this month and obtained by TMZ, showing Lamar incoherently rapping without his shirt on ... talking about drugs, making money without the NBA, and cheating on Khloe Kardashian.

Lamar appears out of it, rapping about making money off his fragrance "Unbreakable," and how he smokes drugs to make "the pain go away." He even drops Kanye's name.

But the crazy part -- Lamar raps, "And when Khloe's out of town / I still be on the DL." His friend then follows up, "You know what it is / We the QU [Queens] pimps / Ask any of these shorties / We ran through their cribs."

Translation: when Khloe's away, Lamar will play.

As we reported, Lamar's currently training hard in Rhode Island, trying to get his ass back in shape for the NBA -- but drugs are still obviously a big part of his life.