aggressive

UK: /əˈgrɛsɪv/ US: /əˈgrɛsɪv/ ,(ə gres′iv)

WordReference Random House Learner's Dictionary of American English © 2025

ag•gres•sive /əˈgrɛsɪv/   adj. 

1. characterized by or tending toward aggression;
   warlike;
   hostile:
   the aggressive nature of the dictator's actions.
2. vigorously energetic:
   an aggressive approach to solving problems.

ag•gres•sive•ly, adv. 
ag•gres•sive•ness, n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2025

ag•gres•sive  (ə gres′iv), adj. 

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. Stock Exchange, Business emphasizing maximum growth and capital gains over quality, security, and income:
   an aggressive mutual fund.
6. • (of a disease or tumor) highly invasive and difficult or impossible to treat successfully.
   • Medicine pertaining to a risky surgery or treatment, or to a medication that has grave side effects:
     aggressive chemotherapy.

• aggress(ion) + -ive 1815–25

ag•gres′sive•ly, adv. 
ag•gres′sive•ness, ag•gres•siv•i•ty  (ag′re siv′i tē), n.  Synonyms

• 1. . pugnacious, militant.
• 2. . forceful, enterprising, assertive.

Antonyms

• 1. . friendly.
• 2. . retiring, shy, timid, hesitant.

aggressive, +adj. 

1. Medicine (of a disease or tumor) highly invasive and 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.

Collins Concise English Dictionary © HarperCollins Publishers::

aggressive / əˈɡrɛsɪv/ adjective

1. quarrelsome or belligerent
2. assertive; vigorous

agˈgressively adverb

agˈgressiveness noun