Luke Rockhold Discusses Greg Hardy

UFC superstar Luke Rockhold is BLASTING Greg Hardy and anyone considering training the ex-NFL star ... saying, "it's crazy to think that someone would actually train this guy."

Rockhold joined the "TMZ Sports" TV show ... when he was asked about Hardy's plan to hang up his cleats and fight mixed martial arts.

Luke absolutely goes in on Hardy ... calling the domestic violence accusations against him "beyond anything of what a normal human is capable of."

FYI -- Hardy was convicted of domestic violence in '14 ... before the guilty verdict was dismissed after the accuser stopped cooperating with authorities.

Check out the clip ... it's clear Rockhold vehemently feels Hardy has no place in MMA.