speed vs accelerate

speed is a noun but accelerate is not a noun.

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

As verbs, speed and accelerate are synonyms defined as:

Other synonyms of speed include quicken, speed up.

As verbs, speed and accelerate are synonyms defined as:

Other synonyms of speed include speed up.

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