The term 'muffle, as a sound' can be summarized by the crossword solution 'DEADEN, ' which is a 6-letter word. Muffling a sound means to reduce its intensity or volume, making it less audible. This can be done with physical objects such as blankets, pillows, or acoustic foam, or with electronic devices such as noise-cancelling headphones. Muffling a sound is often used to reduce noise pollution or to create a more peaceful environment.