hardcore
Concise Oxford English Dictionary © 2008 Oxford University Press:
hard core
▶noun
- 1 the most active, committed, or doctrinaire members of a group.
- 2 (usu. hardcore) popular music that is experimental in nature and typically characterized by high volume and aggressive presentation.
- 3 pornography of a very explicit kind. [as modifier] hard-core porn.
- 4 Brit. broken bricks and rubble used as a filling or foundation in building.
'hardcore' also found in these Oxford entries:

