UFC's Kamaru Usman: Colby Covington Has 'P***y-itis' ... And I Got the Cure!

UFC's rising star Kamaru Usman is sick and tired of Colby Covington duckin' him -- so he's callin' a spade a spade.

Or, in his words, a "p***y" a "p***y."

"Colby's not f**kin' with me," Usman told TMZ Sports. "Classic case of p***y-itis."

Covington hasn't been making any friends since joining the UFC -- dropping 'Star Wars' spoilers on social media, calling Brazilians "filthy animals" ... and, most recently, going WAY overboard to diss "Platinum" Mike Perry.

Kamaru says he's had enough -- and tells us literally THOUSANDS of UFC fans told him to "knock (Colby) the f*ck out" at UFC Fight Night: Orlando over the weekend.

Usman's a few spots lower than Covington in the welterweight rankings ... but he's 7-0 in the UFC and is expected to get a top opponent next.