malarky vs idle words

malarky and idle words both are nouns.

Word	Noun	Adjective	Verb	Adverb
malarky	Yes	No	No	No
idle words	Yes	No	No	No

As nouns, malarky and idle words are synonyms defined as:

Other synonyms of malarky include jazz, malarkey, nothingness, wind.

malarky (noun)	idle words (noun)
empty rhetoric or insincere or exaggerated talk	empty rhetoric or insincere or exaggerated talk