Harsh; unrelenting.
Disagreeably precise or penetrating.
Savagely violent, vicious, ruthless, or cruel.
Crude or unfeeling in manner or speech.
Direct and without attempt to disguise unpleasantness.
In extreme metal, to describe the speed of the music and the density of riffs.
Emotionally hardened; unfeeling and indifferent to the suffering/feelings of others.
Having calluses, or relating to calluses.