aggressive in WordNet English dictionary

1. having or showing determination and energetic pursuit of your ends
   "an aggressive businessman"; "an aggressive basketball player"; "he was aggressive and imperious; positive in his convictions"; "aggressive drivers"
   aggressive 
   
2. characteristic of an enemy or one eager to fight
   "aggressive acts against another country"; "a belligerent tone"
   aggressive  belligerent 
   
3. tending to spread quickly
   "an aggressive tumor"
   aggressive  fast-growing  strong-growing