Onomatopoeic word describing noisy chatter or a hubbub (many people talking loudly).
居酒屋は週末でがやがやしていた。
The izakaya was noisy with chatter on the weekend.
会場の外からがやがやした声が聞こえる。
You can hear a hubbub of voices from outside the venue.
子どもたちが公園でがやがや遊んでいる。
Children are noisily playing in the park.
An older/archaic onomatopoeia describing loud or sustained laughter; somewhat literary or old-fashioned in modern use.
彼の冗談にみんなががやがや笑った（古めかしい表現）。
Everyone laughed loudly at his joke (somewhat old-fashioned expression).