The UFC star tells TMZ Sports he got fed up with all the curse words Conor was dropping at their nasty press conference on Thursday ... and says they need to be better role models!

"This is what I don't like when too much people cursing," Khabib said ... "Too many young guys like follow us ... I don't want to be a bad example for young generation people."

Conor dropped more bad words than a "Def Comedy Jam" act -- calling Khabib every dirty word in the book ... from "little rat" to "fanboy bitch" and "backwards c*nt."

Khabib says he refuses to engage in expletive warfare -- "I wanna be good [role] model."

As for whether Conor got under his skin at the presser, Khabib scoffed ... saying he's confident he'll "smash" McGregor when they face off at UFC 229 on Oct. 6.