na-adjective
Describes a person, group, or activity that is lively and full of action. Often used for someone who proactively engages in many things.
彼はとても活動的な人で、週末はいつも外に出かけている。
He is a very active person and always goes out on weekends.
このクラブは活動的なメンバーが多い。
This club has many energetic members.