Conor McGregor's back in hot water ... this time the UFC superstar is being dragged for using the n-word in a super offensive rant.
The 36-year-old, who's no stranger to controversy, unleashed the derogatory tirade on X early Friday morning ... in a post where he went off on his nemesis, Khabib Nurmagomedov.
The diatribe -- which featured two uses of the N-word -- seemed to be unprompted .