hiso-hiso
Speaking in hushed tones so others cannot hear. Often implies sharing secrets or talking about someone behind their back.
💡Coworkers whispering in the hallway — 'They were talking hiso-hiso about the new boss.'
二人はひそひそ話をしていた。
The two of them were whispering hiso-hiso.
The students were ___ during the exam about the answers.
生徒たちは試験中に答えについて○○話していた。