fier-, feroci- +

1. Marked by extreme and violent energy.
2. Savagely fierce, cruel, or violent.
3. Marked by unrelenting intensity, very great, extreme: "The ferocious heat has been unbearable."

1. In a physically fierce manner: "The evening silence was disturbed by dogs barking ferociously."
2. Exhibiting or given to extreme fierceness and unrestrained violence and brutality.

1. Exhibiting or given to extreme fierceness and unrestrained violence and brutality.
2. A trait of extreme cruelty.

1. Characterized by being wild or turbulent.
2. Savage wildness or fierceness; fury; cruelty: "They saw the ferocity of lions fighting over the dead antelope."
3. Fierceness indicating a savage heart.

1. Marked by extreme intensity of emotions or convictions.
2. Inclined to react violently; fervid.
3. Characterized by or showing aggression or anger: "We were startled by the fierce guard dog barking at the fence."
4. Characterized by the violence or intensity of the forces, activity, or participants involved in an activity; such as, a fierce battle or a fierce storm.
5. Deeply and intensely felt and often aggressively expressed.

1. In an emotionally fierce manner: "The mother was fiercely proud of her children."
2. In a physically fierce manner.
3. Having a savage and violent nature; ferocious: "The cat fiercely fought the dog which had attacked her."
4. Extremely severe or violent; terrible.
5. Extremely intense or ardent: "He was fiercely loyal to his family."

1. Eagerness for blood; fury; such as, the fierceness of a lion or a bear.
2. Quick to attack; keenness in anger and resentment.
3. Violence; outrageous passion: "I can't stand his excessive fierceness."
4. Vehemence; fury; impetuosity.