rash vs reckless

rash is a noun but reckless is not a noun.

Word	Noun	Adjective	Verb	Adverb
rash	Yes	Yes	No	No
reckless	No	Yes	No	No

As adjectives, rash and reckless are synonyms defined as:

rash and reckless: marked by defiant disregard for danger or consequences

Other synonyms of rash include foolhardy, heady.

rash (noun)	reckless (noun)
a series of unexpected and unpleasant occurrences
any red eruption of the skin

rash (adjective)	reckless (adjective)
marked by defiant disregard for danger or consequences	marked by defiant disregard for danger or consequences
imprudently incurring risk	characterized by careless unconcern