fairytale vs fairy story

fairytale and fairy story both are nouns.

Word	Noun	Adjective	Verb	Adverb
fairytale	Yes	No	No	No
fairy story	Yes	No	No	No

As nouns, fairytale and fairy story are synonyms defined as:

fairytale and fairy story: a story about fairies; told to amuse children

Other synonyms of fairytale include fairy tale.

As nouns, fairytale and fairy story are synonyms defined as:

fairytale and fairy story: an interesting but highly implausible story; often told as an excuse

Other synonyms of fairytale include cock-and-bull story, fairy tale, song and dance.

fairytale (noun)	fairy story (noun)
a story about fairies; told to amuse children	a story about fairies; told to amuse children
an interesting but highly implausible story; often told as an excuse	an interesting but highly implausible story; often told as an excuse