pell-mell vs harum-scarum

pell-mell is not a noun while harum-scarum is a noun.

Word	Noun	Adjective	Verb	Adverb
pell-mell	No	Yes	No	Yes
harum-scarum	Yes	Yes	No	Yes

As adverbs, pell-mell and harum-scarum are synonyms defined as:

pell-mell (noun)	harum-scarum (noun)
	a reckless impetuous irresponsible person

pell-mell (adjective)	harum-scarum (adjective)
with undue hurry and confusion	cheerfully irresponsible

pell-mell (adverb)	harum-scarum (adverb)
in a wild or reckless manner	in a wild or reckless manner