unregistered vs undocumented

unregistered and undocumented both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unregistered	No	Yes	No	No
undocumented	No	Yes	No	No

unregistered (adjective)	undocumented (adjective)
not registered	lacking necessary documents (as for e.g. permission to live or work in a country)
(of animals) not recorded with or certified by an official breed association
(a boat or vessel) not furnished with official documents