defect vs birth defect

defect and birth defect both are nouns.

Word	Noun	Adjective	Verb	Adverb
defect	Yes	No	Yes	No
birth defect	Yes	No	No	No

As nouns, birth defect is a hyponym of defect; that is, birth defect is a word with a more specific, narrower meaning than defect:

defect (noun)	birth defect (noun)
a mark or flaw that spoils the appearance of something (especially on a person's body)	a defect that is present at birth
a failing or deficiency
an imperfection in an object or machine
an imperfection in a bodily system

defect (verb)	birth defect (verb)
desert (a cause, a country or an army), often in order to join the opposing cause, country, or army