Is it farther or further?
"trash," 1915, from American Yiddish shlak, from German Schlacke "dregs, scum, dross" (see slag (n.)). Alternative etymology [OED] is from Yiddish shlogn "to strike" (cf. German schlagen; see slay). Derived form schlockmeister "purveyor of cheap merchandise" is from 1965. Adjectival form schlocky is attested from 1968; schlock was used as an adjective from 1916.
: unlike all those schlock filmsnoun
(also schlack or schlag or shlock) Inferior merchandise; an inferior product; crap, junk: That ''Macbird'' is a piece of schlock/ are bringing out schlock so they can pay for the books they care about (1915+)
[fr Yiddish fr German schlag, ''a blow,'' perhaps because the merchandise has been knocked around, or knocked down, or perhaps because, as Eric I Bromberg wrote in American Speech in 1938, ''to schlach is to cut or raise a price according to a customer''; the New York Times speculated in 1922 that the underworld use schlock, ''a broken lot of loot,'' was adopted because junk had recently come to mean ''narcotics, dope'']