active

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Being in physical motion: active fish in the aquarium.
2. adj. Functioning or capable of functioning.
3. adj. Marked by energetic activity; busy: active stock and bond markets; spent an active day sightseeing.
4. adj. Involving or requiring physical exertion and energy: an active workout at the gym.
5. adj. Being in a state of action; not quiescent: active hostilities along the border.
6. adj. Erupting or liable to erupt; not dormant: an active volcano.
7. adj. Marked by or involving direct participation: took an active interest in politics; played an active role on the committee.
8. adj. Currently in use or effect: an active membership.
9. adj. Openly acknowledged or expressed: an active dislike of the new neighbors.
10. adj. Producing an intended action or effect: active ingredients.
11. adj. Grammar Indicating that the subject of the sentence is performing or causing the action expressed by the verb. Used of a verb form or voice.
12. adj. Grammar Expressing action rather than a state of being. Used of verbs such as run, speak, and move.
13. adj. Producing profit, interest, or dividends: active accounts; active stocks.
14. adj. Electronics Being a source of electrical energy, as a generator.
15. adj. Electronics Capable of converting or amplifying voltages or currents, as a diode or transistor.
16. adj. Being on full military duty and receiving full pay.
17. n. Grammar The active voice.
18. n. Grammar A construction or form in the active voice.
19. n. A participating member of an organization: union actives.

Century Dictionary and Cyclopedia

1. Having the power or property of acting; tending to cause change or communicate action or motion; capable of exerting influence: opposed to passive: as, attraction is an active power.
2. Specifically In medicine, acting quickly; producing immediate effects: as, active remedies or treatment.
3. Having the power of quick motion, or disposition to move with speed; nimble; lively; brisk; agile: as, an active animal.
4. Busy; constantly engaged in action; acting with vigor and assiduity: opposed to dull, slow, or indolent: as, an active officer; also to sedentary: as, an active life.
5. In a state of action; marked by movement or operation; in actual progress or motion; not quiescent, dormant, or suspended: as, to take active proceedings against an offender; to engage in active hostilities.
6. Hence In com., marked by quickness or frequency; brisk; lively; coming or moving freely or abundantly: as, an active trade or demand for goods; active freights or stocks. Requiring action or exertion; practical; operative; producing real effects: opposed to speculative: as, the active duties of life; the active powers of the mind.
7. In grammar, signifying the performance and not the endurance of an action: opposed to passive. Said of a verb or verb-form, and used especially in the case of languages which, like Latin, have a nearly complete passive conjugation of the verb, or else, like Greek and Sanskrit, a partial one; but also, less properly, of those which, like English and French, have a system of verb-phrases with passive meaning, made with an auxiliary. Some grammarians (quite improperly) use active as equivalent to transitive.
8. Reid uses the term to denote the will, appetites, affections, etc.; but that use has been generally condemned.
9. The state of having a place on the active list, under full pay: used in contradistinction to being on the retired list, under reduced pay.
10. Active regards either mind or body; there is no sinister sense of the word. The activity may be merely for its own sake. Active is opposed to lazy, inert, or quiescent: an active mind, life, person.
11. Busy is active about something that is supposed to be useful. As applied to disposition, the word has acquired a bad sense, that of meddlesome: a busybody; he is too busy about others' affairs. An officious person is one whose efforts to be active or busy for others' benefit come, through his lack of judgment, to be regarded as annoying or intrusive. See impertinent.
12. In psychology, representative of a type of character whose dominant characteristic is a natural and constantly renewed tendency to action.

Wiktionary

1. adj. Having the power or quality of acting; causing change; communicating action or motion; acting; — opposed to passive, that receives; as, certain active principles; the powers of the mind.
2. adj. Quick in physical movement; of an agile and vigorous body; nimble; as, an active child or animal.
3. adj. In action; actually proceeding; working; in force; — opposed to quiescent, dormant, or extinct.
4. adj. Given to action; constantly engaged in action; energetic; diligent; busy; — opposed to dull, sluggish, indolent, or inert; as, an active man of business; active mind; active zeal.
5. adj. Requiring or implying action or exertion; — opposed to sedentary or to tranquil; as, active employment or service; active scenes.
6. adj. Given to action rather than contemplation; practical; operative; — opposed to speculative or theoretical; as, an active rather than a speculative statesman.
7. adj. Brisk; lively; as, an active demand for corn.
8. adj. Implying or producing rapid action.
9. adj. grammar Applied to a form of verb; — opposed to passive. See active voice.
10. adj. grammar Applied to verbs which assert that the subject acts upon or affects something else; transitive.
11. adj. grammar Applied to all verbs that express action as distinct from mere existence or state.
12. adj. gay sexual slang (of a homosexual man) enjoying a role in anal sex in which he penetrates, rather than being penetrated by his partner
13. n. A person or thing that is acting or capable of acting.

GNU Webster's 1913

1. adj. Having the power or quality of acting; causing change; communicating action or motion; acting; -- opposed to passive, that receives; ; the powers of the mind.
2. adj. Quick in physical movement; of an agile and vigorous body; nimble.
3. adj. In action; actually proceeding; working; in force; -- opposed to quiescent, dormant, or extinct
4. adj. Given to action; constantly engaged in action; energetic; diligent; busy; -- opposed to dull, sluggish, indolent, or inert
5. adj. Requiring or implying action or exertion; -- opposed to sedentary or to tranquil
6. adj. Given to action rather than contemplation; practical; operative; -- opposed to speculative or theoretical.
7. adj. Brisk; lively.
8. adj. Implying or producing rapid action
9. adj. Applied to a form of verb; -- opposed to passive. See Active voice, under Voice.
10. adj. Applied to verbs which assert that the subject acts upon or affects something else; transitive.
11. adj. Applied to all verbs that express action as distinct from mere existence or state.

WordNet 3.0

1. adj. disposed to take action or effectuate change
2. adj. in operation
3. n. a person who is a participating member of an organization
4. adj. (used of verbs (e.g. `to run') and participial adjectives (e.g. `running' in `running water')) expressing action rather than a state of being
5. adj. full of activity or engaged in continuous activity
6. adj. characterized by energetic activity
7. adj. engaged in full-time work
8. adj. taking part in an activity
9. n. chemical agent capable of activity
10. adj. tending to become more severe or wider in scope
11. adj. expressing that the subject of the sentence has the semantic function of actor:
12. adj. exerting influence or producing a change or effect
13. adj. (of e.g. volcanos) erupting or liable to erupt
14. adj. engaged in or ready for military or naval operations
15. n. the voice used to indicate that the grammatical subject of the verb is performing the action or causing the happening denoted by the verb
16. adj. (of the sun) characterized by an increased occurrence of sunspots and flares and radio emissions
17. adj. (of e.g. volcanos) capable of erupting