The workshop was designed to be highly interactive, with lots of group activities and discussions.

interactive 是由前缀 inter-（表示"相互"）和形容词 active（活跃的）组成的复合词。字面意思是"相互活跃的"，引申为"互动的"、"交互的"，指参与者之间能够相互交流和影响的活动形式。