hXc is just short for the word hardcore. hardcore is a music genre but also is an attitude and a way of life. Most people who like or are into hXc usually didn't fit in very well with the popular crowd or just didn't feel like they belong there so they found a place where they fit in and had a home and could relate with other people, this was hXc. There are many versions of hXc.
Michael was so hXc when he owned that n00b, but then again when isn't he.