ferocious

Concise Oxford English Dictionary © 2008 Oxford University Press:
ferocious/fəˈrəʊʃəs/

▶adjective

• 1 savagely fierce, cruel, or violent.

• 2 informal very intense or severe.

– derivatives
ferociously adverb,
ferociousness noun,
ferocity noun (pl. ferocities).

– origin C17 (earlier (C16) as ferocity): from L. ferox, feroc- ‘fierce’ + -ious.