playing field vs athletic field

playing field and athletic field both are nouns.

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

As nouns, playing field and athletic field are synonyms defined as:

playing field and athletic field: a piece of land prepared for playing a game

Other synonyms of playing field include field, playing area.

playing field (noun)	athletic field (noun)
a piece of land prepared for playing a game	a piece of land prepared for playing a game
the circumstances under which competition occurs