The term 'Sound of Deflation' can be described by two crossword solutions: PHUT (4 letters) and SSS (3 letters). PHUT is an onomatopoeia, a word that imitates a sound, and is used to describe the sound of a slow leak of air or gas. SSS is an abbreviation for the sound made when air is slowly released, such as a balloon deflating. Together, these two words describe the sound of deflation, which is the process of air or gas escaping from a container.