playing field vs circumstance

playing field and circumstance both are nouns.

Word	Noun	Adjective	Verb	Adverb
playing field	Yes	No	No	No
circumstance	Yes	No	No	No

As nouns, circumstance is a hypernym of playing field; that is, circumstance is a word with a broader meaning than playing field:

playing field: the circumstances under which competition occurs
circumstance: a condition that accompanies or influences some event or activity

playing field (noun)	circumstance (noun)
a piece of land prepared for playing a game	information that should be kept in mind when making a decision
the circumstances under which competition occurs	formal ceremony about important occasions
	a condition that accompanies or influences some event or activity
	the set of facts or circumstances that surround a situation or event