speed vs scudding

speed and scudding both are nouns.

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

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

Other hyponyms of speed include acceleration, quickening, speedup, deceleration, scud.

speed (noun)	scudding (noun)
changing location rapidly	the act of moving along swiftly (as before a gale)
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

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