It seems Rihanna has finally had enough of Chris Brown ... the singer has "unfollowed" her ex-boyfriend on Twitter after he released a new diss track that appears to be aimed at her.
The song in question is a remix of Kanye's TheraFlu -- in which Brown freestyles the verse, "Don't f*ck with my old bitches ... like a bad fur ... every industry n*gga done had her."
He continues, "Trick or treat like a pumpkin ... just to smash her."
Hours after Brown released the track last night, Rihanna stopped following Brown on Twitter -- a HUGE move -- and one that's leading many to assume Rihanna believes the verse is about her.
A short time later, Brown unfollowed Rihanna.
We reached out to Rihanna's rep -- so far, no comment.