Mos Def Is Finally Allowed to Leave South Africa

Mos Def can kiss South Africa goodbye -- he's apologized to the government for trying to use a "world passport" and he's all set to jet back to the U.S.

The rapper will hop on a flight Tuesday night after getting arrested in January for using a false passport. The Department of Home Affairs tells TMZ ... he was granted a valid passport after his mea culpa. We're told the government's dropped its charges.

It's not ALL good -- we're told Mos is now on an "undesirable persons" list with the S.A. gov't.