wishy-washy vs namby-pamby

wishy-washy is not a noun while namby-pamby is a noun.

Word	Noun	Adjective	Verb	Adverb
wishy-washy	No	Yes	No	No
namby-pamby	Yes	Yes	No	No

As adjectives, wishy-washy and namby-pamby are synonyms defined as:

Other synonyms of wishy-washy include gutless, spineless.

wishy-washy (noun)	namby-pamby (noun)
	an insipid weakling who is foolishly sentimental

wishy-washy (adjective)	namby-pamby (adjective)
lacking courage or vitality	lacking courage or vitality