What does "fighting" mean?

Fighting: 2. Occupied in war; being the scene of a battle; as, a fighting field. Pope. A fighting chance, one dependent upon the issue of a struggle. [Colloq.] -- Fighting crab (Zoöl.), the fiddler crab. -- Fighting fish (Zoöl.), a remarkably pugnacious East Indian fish (Betta pugnax), reared by the Siamese for spectacular fish fights.

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