grapevine vs grape vine

grapevine and grape vine both are nouns.

Word	Noun	Adjective	Verb	Adverb
grapevine	Yes	No	No	No
grape vine	Yes	No	No	No

As nouns, grapevine and grape vine are synonyms defined as:

grapevine and grape vine: any of numerous woody vines of genus Vitis bearing clusters of edible berries

Other synonyms of grapevine include grape.

grapevine (noun)	grape vine (noun)
gossip spread by spoken communication	any of numerous woody vines of genus Vitis bearing clusters of edible berries
any of numerous woody vines of genus Vitis bearing clusters of edible berries