Sentence:  He sucked in his breath and kept <WSD>quiet</WSD> while Killpath laid down the sheet again , wound the gold wire stems of his glasses around his ears and then , eying the report as it lay before him on the desk , intoned , `` Acting Lieutenant Gunnar Matson one failed to see that the station keeper was properly relieved two absented himself throughout the entire watch without checking on the station 's activities or the whereabouts of his section sergeants three permitted members of the Homicide Detail of the Inspector's Bureau to arrogate for their own convenience a patrolman who was thereby prevented from carrying on his proper assignment four failed to notify the station commander Acting Captain O. T. Killpath of a homicide occurring in the district five frequented extralegal establishments known as after-hours spots for purposes of an unofficial and purportedly social nature and six '' - he leaned back and peeled off his glasses `` - failed to co-operate with the Acting Captain by returning promptly when so ordered . 
Meaning of the word marked with <WSD> tags:  free of noise or uproar; or making little if any sound