Quietly
Calmly
adverb
Quiet quiet! Do it quietly, please.
しずしず
You know how 静か is しずか? Well, this is the same reading as that. Say it in a whisper with me: "しずしず." Shhh!
私の母は、いつも静々と機械的に家事をこなしていました。
My mom always did housework quietly and mechanically.
いかりくるう妻の横を尻目に、ぼくはただ静々とそうじをしていた。
I was just ignoring my super-angry wife and calmly cleaning our place.
公爵夫人は静々と部屋に入って、公爵にキスをした。
The duchess gracefully entered the room and kissed the duke.