active

adjective

• 1engaging or ready to engage in physically energetic pursuits:although he was seventy he was still robust and active
• moving or tending to move about vigorously or frequently:I couldn’t feel the baby moving, and it was normally very active
• characterized by busy or lively activity:they enjoyed an active social life
• (of a person’s mind or imagination) alert and lively: Caroline nodded slowly, her active mind already racing ahead

• 2participating or engaged in a particular sphere or activity:sexually active teenagers she was an active member of the society
• [predic.] (of a person or animal) pursuing their usual occupation or activity at a particular place or time:tigers are active mainly at night

• 3in operation; working:the old watermill was active until 1960
• (of an electric circuit) capable of modifying its state or characteristics automatically in response to input or feedback: the receiver is continuously active whenever the vehicle ignition is switched on
• (of a volcano) that is erupting or has erupted in historical times: the volcano became active on 28 March last year Etna is Europe’s highest and most active volcano
• (of a disease) in which the symptoms are manifest; not in remission or latent.
• having a chemical or biological effect on something:active ingredients

• 4 Grammar denoting a voice of verbs in which the subject is typically the person or thing performing the action and which can take a direct object (e.g. she loved him as opposed to the passive form he was loved).

noun

• an active form of a verb.