A project management term that pushes for a goal or milestone to be completed on a certain date but key stakeholders are not made aware of this date, the deliverables, or any logical reason why this date was chosen. A Whisper Date usually sets unrealistic expectations that results in people pulling off miracle work to save the ass of the "Whisper Dater".
"Ann are you okay?"
"Chuck presented to the management team this morning and set a 'Whisper Date' of completion for THIS Tuesday without informing the Engineering Team..."
"You know what they say, 'Let it be written... let it be done..'"