hard core
noun
1
- the most active, committed, or doctrinaire members of a group or movement（组织、运动的）中坚力量, 中坚分子; 忠实信徒; 铁杆分子; 恪守教条者：
there is always a hard core of trusty stalwarts
始终存在着一批坚定的忠实支持者
as modifier a hard-core following.铁杆追随者。
1.1
- mass noun popular music that is experimental in nature and typically characterized by high volume and aggressive presentation硬派音乐（一种实验性流行音乐, 其特点为高音量和强有力的表演手段）。
1.2
- mass noun pornography of a very explicit kind（性描写）赤裸裸的色情作品：
as modifier hard-core porn.露骨的色情文学。
2
- mass noun Brit. broken bricks, rubble, or similar solid material used as a filling or foundation in building〈英〉（打地基的）碎石。