sweet melon vine vs sweet melon

sweet melon vine and sweet melon both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweet melon vine	Yes	No	No	No
sweet melon	Yes	No	No	No

As nouns, sweet melon vine and sweet melon are synonyms defined as:

sweet melon vine and sweet melon: any of several varieties of vine whose fruit has a netted rind and edible flesh and a musky smell

Other synonyms of sweet melon vine include Cucumis melo, muskmelon.

sweet melon vine (noun)	sweet melon (noun)
any of several varieties of vine whose fruit has a netted rind and edible flesh and a musky smell	the fruit of a muskmelon vine; any of several sweet melons related to cucumbers
	any of several varieties of vine whose fruit has a netted rind and edible flesh and a musky smell