n. 繁忙, 忙碌

[ noun ]
the state of being or appearing to be actively engaged in an activity
<noun.state>
they manifested all the busyness of a pack of beaversthere is a constant hum of military preparation

busyness \busyness\ n.
the state of being or appearing to be actively engaged in an
activity; as, they manifested all the busyness of a pack of
beavers.
[WordNet 1.5]