n.

1. 活動；活動力[U]
   He once engaged in anti-government activity.

   他一度從事反政府的活動。

2. 行動[U]
   The store was a scene of great activity.

   這家商店顧客盈門。

3. 活躍；敏捷[U]
4. （某一團體的）特殊活動；帶消遣性的活動[P1]
   Stamp collecting is my favorite activity.

   集郵是我最喜愛的消遣。

   The school offers many recreational activities for the students.

   該校為學生提供了很多娛樂活動。

n.

1. a condition in which things are happening or being done.
   ▸busy or vigorous action or movement.
2. an action taken in pursuit of an objective.
   ▸a recreational pursuit.
3. the degree to which something displays its characteristic property or behaviour.