| noun | chemical agent capable of activity |
| noun | the voice used to indicate that the grammatical subject of the verb is performing the action or causing the happening denoted by the verb “`The boy threw the ball' uses the active voice” |
| noun | a person who is a participating member of an organization “the club issues a list of members, both the actives and the retirees” |
| adjective | tending to become more severe or wider in scope “active tuberculosis” |
| adjective | engaged in or ready for military or naval operations “on active duty” |
| adjective | disposed to take action or effectuate change “a director who takes an active interest in corporate operations” |
| adjective | taking part in an activity “an active member of the club” |
| adjective | characterized by energetic activity “an active toddler” |
| adjective | exerting influence or producing a change or effect “an active ingredient” |
| adjective | full of activity or engaged in continuous activity “an active seaport” |
| adjective | in operation “keep hope alive” |
| adjective | (of the sun) characterized by an increased occurrence of sunspots and flares and radio emissions |
| adjective | expressing that the subject of the sentence has the semantic function of actor: “Hemingway favors active constructions” |
| adjective | (used of verbs (e.g. `to run') and participial adjectives (e.g. `running' in `running water')) expressing action rather than a state of being |
| adjective | (of e.g. volcanos) capable of erupting |
| adjective | (of e.g. volcanos) erupting or liable to erupt “active volcanos” |
| adjective | engaged in full-time work “active duty” |
| active | adjective | exerting influence or producing a change or effect |
| activeness | noun | the state of being active |
| activity | noun | an organic process that takes place in the body |
| active | noun | a person who is a participating member of an organization |
| aliveness | noun | the condition of living or the state of being alive |