perjurer vs false witness

perjurer and false witness both are nouns.

Word	Noun	Adjective	Verb	Adverb
perjurer	Yes	No	No	No
false witness	Yes	No	No	No

As nouns, perjurer and false witness are synonyms defined as:

perjurer and false witness: a person who deliberately gives false testimony

perjurer (noun)	false witness (noun)
a person who deliberately gives false testimony	a person who deliberately gives false testimony