whizz along vs speed

whizz along is not a noun while speed is a noun.

Word	Noun	Adjective	Verb	Adverb
whizz along	No	No	Yes	No
speed	Yes	No	Yes	No

As verbs, speed is a hypernym of whizz along; that is, speed is a word with a broader meaning than whizz along:

Other hypernyms of whizz along include hurry, travel rapidly, zip.

whizz along (noun)	speed (noun)
	changing location rapidly
	a central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression
	a rate (usually rapid) at which something happens
	the ratio of the focal length to the diameter of a (camera) lens system
	distance travelled per unit time

whizz along (verb)	speed (verb)
move along very quickly	move faster
	cause to move faster
	move very fast
	travel at an excessive or illegal velocity
	move hurridly