speed vs flash

speed and flash both are nouns.

Word	Noun	Adjective	Verb	Adverb
speed	Yes	No	Yes	No
flash	Yes	Yes	Yes	No

As verbs, flash is a hyponym of speed; that is, flash is a word with a more specific, narrower meaning than speed:

Other hyponyms of speed include barge, push forward, thrust ahead, buck, charge, shoot, shoot down, tear, dart, dash, scoot, scud, shoot.

speed (noun)	flash (noun)
changing location rapidly	a lamp for providing momentary light to take a photograph
a central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression	a bright patch of color used for decoration or identification
a rate (usually rapid) at which something happens	a momentary brightness
the ratio of the focal length to the diameter of a (camera) lens system	a sudden brilliant understanding
distance travelled per unit time	a short news announcement concerning some on-going news story
	a burst of light used to communicate or illuminate
	a gaudy outward display
	a sudden intense burst of radiant energy
	a short vivid experience
	a very short time (as the time it takes the eye to blink or the heart to beat)

speed (adjective)	flash (adjective)
	tastelessly showy

speed (verb)	flash (verb)
move faster	appear briefly
cause to move faster	emit a brief burst of light
move very fast	make known or cause to appear with great speed
travel at an excessive or illegal velocity	protect by covering with a thin sheet of metal
move hurridly	run or move very quickly or hastily
	gleam or glow intermittently
	display proudly; act ostentatiously or pretentiously
	expose or show briefly