Bustling or busy; lively and prosperous (places or events full of activity).
休日の商店街はとても賑やかだ。
The shopping street is very busy on holidays.
祭りの屋台で町が一晩中賑やかだった。
The town was lively all night with festival stalls.
新しいカフェができて通りが賑やかになった。
A new café opened and the street became bustling.
Lively or noisy (in terms of voices, music, atmosphere); cheerful and merry.
パーティーは賑やかで皆が楽しんでいた。
The party was lively and everyone was enjoying themselves.
子どもたちの声で公園が賑やかになった。
The park became lively with the children's voices.
彼女の誕生日は賑やかに祝われた。
Her birthday was celebrated cheerfully/lively.