One who is aggressive.

(US, LGBT, Black lesbian slang) A (Black) woman who presents as masculine; a butch.

Characterized by aggression; unjustly attacking; prone to behave in a way that involves attacking or arguing.

(programming) Of heuristics, source code optimization techniques, etc.: exploiting every opportunity to be applied.

(pathology, of a tumour or disease) That spreads quickly or extensively; virulent; malignant.

(finance) Involving high risk for potentially high reward.

(US, LGBT, Black lesbian slang) Female but having a male or masculine gender presentation: butch.