walkover vs child's play

walkover and child's play both are nouns.

Word	Noun	Adjective	Verb	Adverb
walkover	Yes	No	No	No
child's play	Yes	No	No	No

As nouns, walkover and child's play are synonyms defined as:

Other synonyms of walkover include breeze, cinch, duck soup, picnic, piece of cake, pushover, snap.

walkover (noun)	child's play (noun)
any undertaking that is easy to do	any undertaking that is easy to do
backbends combined with handstands	activity by children that is guided more by imagination than by fixed rules