antidote vs counterpoison

antidote and counterpoison both are nouns.

Word	Noun	Adjective	Verb	Adverb
antidote	Yes	No	No	No
counterpoison	Yes	No	No	No

As nouns, antidote and counterpoison are synonyms defined as:

antidote and counterpoison: a remedy that stops or controls the effects of a poison

antidote (noun)	counterpoison (noun)
a remedy that stops or controls the effects of a poison	a remedy that stops or controls the effects of a poison