say it: AK-tiv
active is an adjective and noun meaning "tending to become more severe or wider in scope". It carries 17 recorded senses.
tending to become more severe or wider in scope
“active tuberculosis”
pathology
engaged in or ready for military or naval operations
“on active duty”
“the platoon is combat-ready”
“review the fighting forces”
military
taking part in an activity
“an active member of the club”
“he was politically active”
“the participating organizations”
(of the sun) characterized by an increased occurrence of sunspots and flares and radio emissions
astronomy
expressing that the subject of the sentence has the semantic function of actor: "Hemingway favors active constructions"
grammar
chemical agent capable of activity
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”
a person who is a participating member of an organization
“the club issues a list of members, both the actives and the retirees”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for active come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.