hauberk vs byrnie

hauberk and byrnie both are nouns.

Word	Noun	Adjective	Verb	Adverb
hauberk	Yes	No	No	No
byrnie	Yes	No	No	No

As nouns, hauberk and byrnie are synonyms defined as:

hauberk and byrnie: a long (usually sleeveless) tunic of chain mail formerly worn as defensive armor

hauberk (noun)	byrnie (noun)
a long (usually sleeveless) tunic of chain mail formerly worn as defensive armor	a long (usually sleeveless) tunic of chain mail formerly worn as defensive armor