Whispering or private conversation, especially talking quietly during public settings like classes or meetings; often implies disturbance or impropriety.
授業中の私語は先生に注意される。
Whispering during class will get you warned by the teacher.
映画館では私語を慎んでください。
Please refrain from private talking in the movie theater.
会議中の私語が多くて進行が遅れた。
There was a lot of whispering during the meeting, and progress was delayed.