'activity' definitions:

Definition of 'activity'

(from WordNet)
noun
Any specific behavior; "they avoided all recreational activity" [ant: inactivity]
noun
The state of being active; "his sphere of activity"; "he is out of action" [syn: action, activity, activeness] [ant: inaction, inactiveness, inactivity]
noun
An organic process that takes place in the body; "respiratory activity" [syn: bodily process, body process, bodily function, activity]
noun
(chemistry) the capacity of a substance to take part in a chemical reaction; "catalytic activity"
noun
A process existing in or produced by nature (rather than by the intent of human beings); "the action of natural forces"; "volcanic activity" [syn: natural process, natural action, action, activity]
noun
The trait of being active; moving or acting rapidly and energetically; "the level of activity declines with age" [syn: activeness, activity] [ant: inactiveness, inactivity, inertia]

Synonyms of 'activity'

From: Moby Thesaurus