How do you spell Hannukah?
also hard-core; 1936 (n.); 1951 (adj.); from hard + core. Original use seems to be among economists and sociologists. Extension to pornography is attested by 1966. Also the name of a surfacing material.
Essential and uncompromising; unmitigated: a hard-core Republican/ hard-core pornography (1951+)
Pornography that openly depicts complete sex acts: He sort of likes dirty stuff, but not real hard core (1970s+)