1To become lively, animated, or active; to liven up or pick up (in energy or activity).
商店街に観光客が増えて、通りが活気付いてきた。
With more tourists arriving, the shopping street has started to liven up.
新しい店ができて町全体が活気づいた。
A new shop opened and the whole town became more active.
大会が始まると会場は一気に活気付いた。
When the tournament began, the venue quickly became lively.