blood relative vs sib

blood relative and sib both are nouns.

Word	Noun	Adjective	Verb	Adverb
blood relative	Yes	No	No	No
sib	Yes	No	No	No

As nouns, blood relative and sib are synonyms defined as:

blood relative and sib: one related by blood or origin; especially on sharing an ancestor with another

Other synonyms of blood relative include blood relation, cognate.

blood relative (noun)	sib (noun)
one related by blood or origin; especially on sharing an ancestor with another	one related by blood or origin; especially on sharing an ancestor with another
	a person's brother or sister