is returning fire in his war with Onyx
rapper Fredro Starr
-- telling TMZ, he ain't one bit afraid of the guy's death threats ... claiming, Starr's "a midget" who "can't even reach my knee."
X tells us, "I am not worried about him ... All he is is a sitcom Moesha gangsta. He should just stick to being a reality gangsta cause that's about all he's good for." (FYI, Starr appeared on the show "Moesha
" back in the 90s.)