double check vs countercheck

double check and countercheck both are nouns.

Word	Noun	Adjective	Verb	Adverb
double check	Yes	No	No	No
countercheck	Yes	No	Yes	No

As nouns, double check and countercheck are synonyms defined as:

double check and countercheck: something that checks the correctness of a previous check

double check (noun)	countercheck (noun)
something that checks the correctness of a previous check	something that checks the correctness of a previous check
	a check that restrains another check

double check (verb)	countercheck (verb)
	check a second time
	oppose or check by a counteraction