One who is aggressive.
A (Black) woman who presents as masculine; a butch.
Female but having a male or masculine gender presentation: butch.
Involving high risk for potentially high reward.
That spreads quickly or extensively; virulent; malignant.
Characterized by aggression; unjustly attacking; prone to behave in a way that involves attacking or arguing.
Of heuristics, source code optimization techniques, etc.: exploiting every opportunity to be applied.
The natural inclination to do whatever is necessary to succeed (including extreme violence)
Used other than figuratively or idiomatically: see killer, instinct.