active

engaged in or ready for military or naval operations

“on active duty”

engaged in full-time work

“active duty”

exerting influence or producing a change or effect

“an active ingredient”

expressing that the subject of the sentence has the semantic function of actor:

“Hemingway favors active constructions”

full of activity or engaged in continuous activity

“an active seaport”

capable of erupting

erupting or liable to erupt

“active volcanos”

characterized by an increased occurrence of sunspots and flares and radio emissions

tending to become more severe or wider in scope

“active tuberculosis”

chemical agent capable of activity

and participial adjectives (e.g. `running' in `running water')) expressing action rather than a state of being

taking part in an activity

“an active member of the club”