The term 'slowly disappear' can be described by four crossword solutions: FADE (4 letters), EVANESCE (8 letters), ERODE (5 letters), and FADEOUT (7 letters). FADE is a gradual decrease in brightness or intensity, while EVANESCE is to gradually vanish from sight or memory. ERODE is to gradually wear away by natural processes, such as wind or water, and FADEOUT is a gradual decrease in sound or image intensity. Finally, fadeaway is to gradually disappear or become less noticeable. All of these words describe the process of something slowly disappearing.