duck soup vs walkover

duck soup and walkover both are nouns.

Word	Noun	Adjective	Verb	Adverb
duck soup	Yes	No	No	No
walkover	Yes	No	No	No

As nouns, duck soup and walkover are synonyms defined as:

Other synonyms of duck soup include breeze, child's play, cinch, picnic, piece of cake, pushover, snap.

duck soup (noun)	walkover (noun)
any undertaking that is easy to do	any undertaking that is easy to do
	backbends combined with handstands