Active; energetic; inclined to take part in activities — describes someone or something that is lively or proactive.
彼女はとても活動的で、週末はいつも山登りに行っている。
She is very active and always goes mountain climbing on weekends.
クラブの活動に活動的に参加する学生が増えた。
More students have been actively participating in club activities.
高齢者でも適度に活動的な生活は健康に良い。
Even for elderly people, a moderately active lifestyle is good for health.