soy sauce vs soy

soy sauce and soy both are nouns.

Word	Noun	Adjective	Verb	Adverb
soy sauce	Yes	No	No	No
soy	Yes	No	No	No

As nouns, soy sauce and soy are synonyms defined as:

soy sauce (noun)	soy (noun)
thin sauce made of fermented soy beans	the most highly proteinaceous vegetable known; the fruit of the soybean plant is used in a variety of foods and as fodder (especially as a replacement for animal protein)
	thin sauce made of fermented soy beans
	erect bushy hairy annual herb having trifoliate leaves and purple to pink flowers; extensively cultivated for food and forage and soil improvement but especially for its nutritious oil-rich seeds; native to Asia
	a source of oil; used for forage and soil improvement and as food