quietening (?.)

• analgesic
• anodyne
• appeasing
• calmant
• calmative
• calming
• cradling
• depressant
• dreamy
• drowsy
• gentling
• hushing
• hypnotic
• lulling
• mollifying
• narcotic
• pacifying
• paregoric
• restful
• rocking
• sedative
• sleep-inducing
• somnifacient
• somniferous
• soothful
• soothing
• soporific
• stilling
• tranquilizing