Activity

n. state of being active; specific act, pursuit, undertaking; action, bustle; spryness, liveliness; something that a person does for pleasure or as an interest

Activity may mean:action, in generalActivity, an alternative name for the game charadesActivity, a task.Activity, the ability of a piece to influence the game in chessActivity, the rate of a catalytic reaction, such as enzyme activity, in physical chemistry and enzymologyactivity (chemistry), the effective concentration of a solute for the purposes of mass action activity (project management)activity (radioactivity), the number of disintegrations per secondactivity (software engineering)activity (soil mechanics)activity diagram, a diagram representing activities in UMLHMS Activity, an aircraft carrier of the Royal Navy
See more at Wikipedia.org...

Noun
1. any specific activity; "they avoided all recreational activity"
(antonym) inactivity
(hypernym) act, human action, human activity
(hyponym) variation, variance
2. the state of being active; "his sphere of activity"; "he is out of action"
(synonym) action, activeness
(antonym) inaction, inactivity, inactiveness
(hypernym) state
(hyponym) agency
(attribute) active
3. an organic process that takes place in the body; "respiratory activity"
(synonym) bodily process, body process, bodily function
(hypernym) organic process, biological process
(hyponym) control
4. (chemistry) the capacity of a substance to take part in a chemical reaction; "catalytic activity"
(hypernym) capability, capacity
(classification) chemistry, chemical science
5. a process existing in or produced by nature (rather than by the intent of human beings); "the action of natural forces"; "volcanic activity"
(synonym) natural process, natural action, action
(hypernym) process
(hyponym) radiation
6. the trait of being active; moving or acting rapidly and energetically; "the level of activity declines with age"
(synonym) activeness
(hypernym) trait
(hyponym) animation, spiritedness, invigoration, brio, vivification
(attribute) active

(n.)
The state or quality of being active; nimbleness; agility; vigorous action or operation; energy; active force; as, an increasing variety of human activities.
  

noun
what something does; the drug's activity did not last more than a few hours
antibacterial activity = effective action against bacteria