The term 'extremely violent' can be described by three crossword solutions: VICIOUS (7 letters), TABOO (5 letters), and RABID (5 letters). VICIOUS is an adjective meaning cruel or violent, often with the intention of causing harm. TABOO is an adjective meaning forbidden or prohibited by law, custom, or morality. RABID is an adjective meaning extremely violent or aggressive, often in a way that is considered socially unacceptable. Together, these three words describe something that is very violent and aggressive, and likely not accepted by society.