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, especially 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.
    1. (of a disease or tumor) spreading rapidly or highly invasive; difficult or impossible to treat successfully.
    2. pertaining to a risky surgery or treatment, or to a medication that has grave side effects: aggressive chemotherapy.

Origin of aggressive

First recorded in 1815–25; aggress(ion) + -ive
Related formsag·gres·sive·ly, adverbag·gres·sive·ness, ag·gres·siv·i·ty [ag-re-siv-i-tee] /ˌæg rɛˈsɪv ɪ ti/, nounan·ti·ag·gres·sive, adjectivean·ti·ag·gres·sive·ly, adverban·ti·ag·gres·sive·ness, nounhy·per·ag·gres·sive, adjectivehy·per·ag·gres·sive·ly, adverbhy·per·ag·gres·sive·ness, nouno·ver·ag·gres·sive, adjectiveo·ver·ag·gres·sive·ly, adverbo·ver·ag·gres·sive·ness, nounpre·ag·gres·sive, adjectivepre·ag·gres·sive·ly, adverbpre·ag·gres·sive·ness, nounpseu·do·ag·gres·sive, adjectivepseu·do·ag·gres·sive·ly, adverbsu·per·ag·gres·sive, adjectiveun·ag·gres·sive, adjectiveun·ag·gres·sive·ly, adverbun·ag·gres·sive·ness, noun
Can be confusedaggressive passive

Synonyms for aggressive

Antonyms for aggressive Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for overaggressive


  1. excessively quarrelsome or belligerent


  1. quarrelsome or belligerentan aggressive remark
  2. assertive; vigorousan aggressive business executive
Derived Formsaggressively, adverbaggressiveness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for overaggressive



1791, from Latin aggress-, past participle stem of aggredi (see aggression) + -ive. In psychological use from 1913, first in translations of Freud. Related: Aggressively; aggressiveness.

Online Etymology Dictionary, © 2010 Douglas Harper

overaggressive in Medicine


  1. Characterized by aggression.
  2. Inclined to behave in a hostile fashion.
  3. Tending to spread quickly, as a tumor; fast-growing.
  4. Characterized by or inclined toward vigorous or intensive medical treatment.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.