fierce in WordNet English dictionary

1. violently agitated and turbulent
   "boisterous winds and waves"; "the fierce thunders roar me their music"- Ezra Pound; "rough weather"; "rough seas"
   boisterous  fierce  rough 
   
2. ruthless in competition
   "cutthroat competition"; "bowelless readiness to take advantage"
   cutthroat  fierce  bowelless 
   
3. marked by extreme and violent energy
   "a ferocious beating"; "fierce fighting"; "a furious battle"
   ferocious  fierce  furious  savage 
   
4. marked by extreme intensity of emotions or convictions; inclined to react violently; fervid
   "fierce loyalty"; "in a tearing rage"; "vehement dislike"; "violent passions"
   fierce  tearing  vehement  violent  trigger-happy