RICK ROSS ENGAGEMENT OFF WITH MODEL ...

Rick Ross and Lira Galore have called off their engagement, less than 2 months after making the leap.

We're told they had a major blowout, although it's unclear what it was about -- but it was serious enough that Lira moved her stuff out of Rozay's Georgia mansion.

Ross spontaneously popped the question back in mid-September while they were jewelry shopping in New York. They'd only been dating a few months at that point.

As for the giant 11 carat, $350k rock he gave Lira ... so far there's been no discussion on whether she'll return it. She still had it on her ring finger in a photo she posted a day ago.

The good news for Rick -- legally speaking, the ring is a gift in contemplation of marriage. Translation: Lira gotta give it back.

Though she might want to reconcile ... after talking to a lawyer.