speed vs bustle about

speed is a noun but bustle about is not a noun.

Word	Noun	Adjective	Verb	Adverb
speed	Yes	No	Yes	No
bustle about	No	No	Yes	No

speed (noun)	bustle about (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

speed (verb)	bustle about (verb)
move faster	move or cause to move energetically or busily
cause to move faster
move very fast
travel at an excessive or illegal velocity
move hurridly