hardcore

adjective
UK /ˈhɑːdkɔː/
US /ˈhɑːrdkɔːr/

Very serious and not changing your mind about something.

She is a hardcore fan of that band and goes to every concert.


OTHER MEANINGS

2. Very strong and not softened in any way, often used about music or movies.

He listens to hardcore punk music.

3. The most active and committed members of a group.

The hardcore of the team stayed late to finish the project.

4. Showing or involving a lot of physical or sexual content.

The movie was too hardcore for young viewers.