Khabib is breaking his silence on Conor McGregor's ugly comments about the undefeated fighter's deceased father ... saying "The Notorious" flat-out has a bad heart.
Nurmagomedov joined "Hotboxin' with Mike Tyson" (and Henry Cejudo) ... when the topic turned to McGregor's now-deleted Tweet about Khabib's late dad, Abdulmanap.
"When [Conor] talked about this, only evil can talk about your father, wife, kids, religion. If you’re normal human, you’re never going to talk about this stuff," Khabib told the combat legends.