the state or quality of being active

There was not much activity in the stock market today. He doesn't have enough physical activity in his life.

a specific deed, action, function, or sphere of action

social activities.

work, esp. in elementary grades at school, that involves direct experience by the student rather than textbook study.

energetic activity; animation; liveliness.

a use of energy or force; an active movement or operation.

normal mental or bodily power, function, or process.

Physical Chemistry . the capacity of a substance to react, corrected for the loss of reactivity due to the interaction of its constituents.

Physics .

the number of atoms of a radioactive substance that disintegrate per unit of time, usually expressed in curies.

radioactivity.

an organizational unit or the function it performs.

noun

idleness , immobility , inactivity , indolence , inertia , laziness , sluggishness , hate , passiveness , quiescence

noun

action , activeness , animation , bustle , enterprise , exercise , exertion , hustle , labor , life , liveliness , motion , movement , act , avocation , bag * , ballgame , bit * , deed , endeavor , entertainment , game , hobby , job , occupation , pastime , project , racket , scene * , scheme , stunt , task , trip , undertaking , venture , work , zoo , ado , agility , briskness , business , flurry , function , operation , pursuit , sprightliness , stir , strenuousness , tumult