–adjective
1.
characterized by or tending toward unprovoked offensives, attacks, invasions, or the like; militantly forward or menacing: aggressive acts against a neighboring country.
2.
making an all-out effort to win or succeed; competitive: an aggressive basketball player.
3.
vigorously energetic, esp. in the use of initiative and forcefulness: an aggressive salesperson.
4.
boldly assertive and forward; pushy: an aggressive driver.
5.
emphasizing maximum growth and capital gains over quality, security, and income: an aggressive mutual fund.
6.
Medicine/Medical .
a.
(of a disease or tumor) spreading rapidly or highly invasive; difficult or impossible to treat successfully.
b.
pertaining to a risky surgery or treatment, or to a medication that has grave side effects: aggressive chemotherapy.