An aggressive person or animal has a quality of anger and determination that makes them ready to attack other people.
belligerent
Some children are much more aggressive than others.
一些孩子比其他孩子好斗得多。
These fish are very aggressive.
这些鱼十分好斗。
People who are aggressive in their work or other activities behave in a forceful way because they are very eager to succeed.
He is respected as a very aggressive and competitive executive.
他是一位锐意进取、竞争意识很强的主管,颇受尊敬。