active

American  

[ak-tiv] / ˈæk tɪv /

adjective

1. engaged in action; characterized by energetic work, participation, etc.; busy.

   an active life.

   Synonyms:

   operative, working, acting

   Antonyms:

   lazy

2. being in a state of existence, progress, or motion.

   active hostilities.

3. involving physical effort and action.

   active sports.

4. having the power of quick motion; nimble.

   active as a gazelle.

   Synonyms:

   sprightly, agile

5. characterized by action, motion, volume, use, participation, etc..

   an active market in wheat; an active list of subscribers.

   Antonyms:

   sluggish

6. causing activity or change; capable of exerting influence (opposed to passive).

   active treason.

7. effective (opposed to inert).

   active ingredients.

8. Grammar. noting or pertaining to a voice of verbal inflection in which typically the subject of the sentence is represented as performing the action expressed by the verb (opposed to passive): Writes in He writes a letter every day is an active verb form.

9. requiring or giving rise to action; practical.

   an active course.

10. Geology. (of a volcano) having erupted within the last 10,000 years and likely to do so again or currently in a state of eruption.

11. Accounting. profitable; busy.

    active accounts.

12. requiring personal effort or attention; not automatic.

    an active alarm system.

13. interest-bearing.

    active paper.

14. Medicine/Medical. acting quickly; producing immediate effects.

    active remedies.

15. Sociology. (of a crowd) engaging in purposeful activity, often of a militant nature.

16. Aerospace. able to transmit signals.

    an active communications satellite.

17. Electronics. (of a device or system) acting as a source of electrical energy, as a generator, or capable of amplifying or converting voltages or currents, as a transistor or diode.

18. (of a solar heating system) accumulating and distributing solar heat by mechanical means.

19. Military. serving on active duty.

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noun

1. Grammar.

   1. the active voice.

   2. a form or construction in the active voice.

2. an active person, member, subscriber, etc..

   The circular was mailed only to the actives on our list.

3. Informal. something showing considerable action or activity.

   On the stock market there was heavy trading in the actives.

active British  

/ ˈæktɪv /

adjective

1. in a state of action; moving, working, or doing something

2. busy or involved

   an active life

3. physically energetic

4. exerting influence; effective

   an active ingredient

5. grammar

   1. denoting a voice of verbs used to indicate that the subject of a sentence is performing the action or causing the event or process described by the verb, as kicked in The boy kicked the football Compare passive

   2. another word for nonstative

6. being fully engaged in military service (esp in the phrase on active service )

7. (of a volcano) erupting periodically; not extinct Compare dormant extinct

8. astronomy (of the sun) exhibiting a large number of sunspots, solar flares, etc, and a marked variation in intensity and frequency of radio emission Compare quiet

9. commerce

   1. producing or being used to produce profit, esp in the form of interest

      active balances

   2. of or denoting stocks or shares that have been actively bought and sold as recorded in the Official List of the London Stock Exchange

10. electronics

    1. containing a source of power

       an active network

    2. capable of amplifying a signal or controlling some function

       an active component

       an active communication satellite

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noun

1. grammar

   1. the active voice

   2. an active verb

2. a member of an organization who participates in its activities

Usage

What is a basic definition of active? Active is an adjective that describes something as involving a lot of energetic work or as engaging in action, operation, or motion. The word active is used in grammar to indicate that the subject of the sentence is performing an action. The word active has other senses as an adjective and a noun. If something or someone is active, a lot of activity is going on or they are using a lot of energy.

• Real-life examples: Professional athletes, firefighters, and police officers usually have very active jobs. An active day at the stock market involves a lot of buying and selling. Ants, birds, and bees live active lives, moving around a lot, compared to animals such as sloths, slugs, and turtles, which stay still much of the time.
• Used in a sentence: Lucy’s cat is very active, chasing shadows and playing with its toys.

Active can also describe something as being in motion or doing things. The word inactive is the opposite of this sense, describing something as sitting around, sleeping, or not functioning.

• Real-life examples: Nocturnal animals are active at night and asleep during the day. If a burglar alarm is active, it has been turned on and is ready to trigger if it detects a person. If a mine or bomb is active, it is operating properly and will explode if something triggers it.
• Used in a sentence: Luckily, the fire alarm was active and quickly detected the fire.

In grammar, the word active refers to the active voice. This term refers to a sentence in which the subject performs the action of the verb. The other English voice is called passive voice, where the subject of the sentence has the action performed on it.

• Active voice: I ran. She drove to the bank. He punched me. 
• Passive voice: The ball was thrown through the window. The building was torn down. I was given an A on the test.

Related Words

Active, energetic, strenuous, vigorous imply a liveliness and briskness in accomplishing something. Active suggests quickness and diligence as opposed to laziness or dilatory methods: an active and useful person. Energetic suggests forceful and intense, sometimes nervous, activity: conducting an energetic campaign. Strenuous implies arduous and zealous activity with a sense of urgency: a strenuous effort. Vigorous suggests strong, effective activity: using vigorous measures to accomplish an end.

Other Word Forms

• actively adverb
• activeness noun
• nonactive adjective
• preactive adjective
• preactiveness noun
• quasi-active adjective
• semiactive adjective
• semiactiveness noun
• superactive adjective
• superactiveness noun

Etymology

Origin of active

First recorded in 1300–50; from Latin āctīvus; replacing Middle English actif, from Middle French, from Latin; see act, -ive

Explanation

Something that is active is characterized by movement and action. That action might be a random or temporary movement, such as someone who is active and exercises only now and then, or something continuous, like an active strain of a virus. Since the adjective active suggests activity, applying it to anything implies some sort of motion or action. A person might be physically active, not sitting around and doing nothing, or mentally active, working the mind. In language, we refer to "the active voice" as one in which the subject does the action, in contrast to the passive voice, a rather boring style where the subject is the receiver of the action. Even in writing, it’s better to be active!

Example Sentences

So far this year, the Eastern District’s six active judges have ordered almost people 2,000 freed.

From Los Angeles Times • Apr. 19, 2026

These include the exotic 48V fully active suspension system, which Ferrari said at the time was the first in production.

From The Wall Street Journal • Apr. 18, 2026

When they last visited in 2018 - then still active members of the Royal Family - tens of thousands of people greeted them on a nine-day tour across Australia.

From BBC • Apr. 18, 2026

Retail sales grew 34% in 2025 to a record 60,119 vehicles, partly due to Polestar’s retail expansion and transition to an active selling model.

From Barron's • Apr. 17, 2026

Though he was an expert at sudden changes of dirt, rock, snow, and ice, being on an active volcano was a new experience for him.

From "Mountain of Fire" by Rebecca E. F. Barone

Related Words

• aggressive
• alive
• bold
• busy
• determined
• diligent
• dynamic
• eager
• energetic
• engaged
• enthusiastic
• forceful
• intense
• keen
• lively
• quick
• ready
• resolute