flashness

As an adjective flashless

is (of a camera) not fitted with a flash.

As a noun flashness is

quality of being flash.

As nouns the difference between flashiness and flashness

is that flashiness is the quality of being flashy while flashness is quality of being flash.

As nouns the difference between flushness and flashness

is that flushness is the state of being flush; abundance while flashness is quality of being flash.