rapid vs speedy

rapid is a noun but speedy is not a noun.

Word	Noun	Adjective	Verb	Adverb
rapid	Yes	Yes	No	No
speedy	No	Yes	No	No

As adjectives, rapid and speedy are synonyms defined as:

rapid and speedy: characterized by speed; moving with or capable of moving with high speed

rapid (noun)	speedy (noun)
a part of a river where the current is very fast

rapid (adjective)	speedy (adjective)
done or occurring in a brief period of time	characterized by speed; moving with or capable of moving with high speed
characterized by speed; moving with or capable of moving with high speed	accomplished rapidly and without delay