- Characterized by aggression: aggressive behavior. (adjective)
- Inclined to behave in an actively hostile fashion: an aggressive regime. (adjective)
- Assertive, bold, and energetic: an aggressive sales campaign. (adjective)
- Of or relating to an investment or approach to investing that seeks above-average returns by taking above-average risks. (adjective)
- Fast growing; tending to spread quickly and invade: an aggressive tumor. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.