hard core 
noun
1The most active, committed, or doctrinaire members of a group or movement: there is always a hard core of trusty stalwarts [as modifier]: a hard-core following...
- The Commission has reduced the fines imposed in the past where participants in cartels have played a reduced role in relation to the hard-core members.
- We know that most crime is committed by a hard-core group of repeat offenders.
- The Roman Catholics surprised everyone by electing a hard-core rightwinger as Pope.
Synonyms
diehard, staunch, dedicated, committed, steadfast, hard-line, dyed-in-the-wool, long-standing;
extreme, entrenched, radical, intransigent, uncompromising, rigid
informal deep-dyed
2 (usually hardcore) [mass noun] Popular music that is experimental in nature and typically characterized by high volume and aggressive presentation.And he's just got a nasty, hardcore, aggressive blues sound in his lead guitar playing....
- From dense post-modern electronica to hardcore techno, Planet Mu constantly surprises.
- I got a bunch of hardcore punk, ska and reggae playing guys and threw them the curve ball.
2.1Pornography of a very explicit kind: [as modifier]: hard-core porn...
- Earlier, the state had censored videos that showed cruel violence and hard-core pornography.
- Computers fed my addiction to hard work, creative planning and hard-core pornography.
- Reality TV plays on a tension similar to Bell's description of hard-core pornography.
3 [mass noun] British Broken bricks, rubble, or similar solid material used as a filling or foundation in building.
- modernista
- modernistic
- modernistically
- modernity
- modernizable
- modernization
- modernization theory
- modernize
- modernizer
- modern jazz
- modern language
- modern Latin
- modernly
- modernness
- modern primitive
- Modern Standard Arabic
- modernus
- modest
- modestly
- modestness
- Modesto
- modesty
- modesty board
- modesty panel
- modesty piece