Meek Mill: Pleads with Judge ... Nicki Minaj Won't Marry a Criminal or Bum

Meek Mill is in court right now fighting for his freedom and his girl ... his lawyer's telling the judge Nicki Minaj "would not marry a criminal or a bum."

Meek is in court on a probation violation ... because he violated the ground rules for leaving Philly. Meek's on probation for a 2009 drug and gun conviction, and one of the conditions of parole is getting approval before traveling. It looks like he violated the rules by going to L.A. for the AMAs.

Nicki is ready to testify on Meek's behalf. His lawyer told the judge his client and Nicki are serious about getting married.

Nicki added fuel to the fire by posting a pic Wednesday of a massive ring on her hand ... sure looks like an engagement ring.