The antonyms for the word "flashes on" can be described as follows- dull, fade, decrease, vanish, evaporate, dim, blur, extinguish, disappear, fade away. These words signify the opposite of the action of something suddenly appearing or being remembered in one's mind. The word "dull" means lacking in brightness, excitement or interest. "Vanish" means to disappear suddenly or completely. "Extinguish" means to bring to an end or put an end to something. These antonyms represent a contrasting image to the vivid and sharp memory presented by the word "flash on," and imply that something has lost its appeal or presence in one's mind.