speedy vs rapid

speedy is not a noun while rapid is a noun.

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

As adjectives, speedy and rapid are synonyms defined as:

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

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

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