soft market vs buyers' market

soft market and buyers' market both are nouns.

Word	Noun	Adjective	Verb	Adverb
soft market	Yes	No	No	No
buyers' market	Yes	No	No	No

As nouns, soft market and buyers' market are synonyms defined as:

soft market and buyers' market: a market in which more people want to sell than want to buy

Other synonyms of soft market include buyer's market.

soft market (noun)	buyers' market (noun)
a market in which more people want to sell than want to buy	a market in which more people want to sell than want to buy