stranger vs intruder

stranger and intruder both are nouns.

Word	Noun	Adjective	Verb	Adverb
stranger	Yes	No	No	No
intruder	Yes	No	No	No

As nouns, intruder is a hypernym of stranger; that is, intruder is a word with a broader meaning than stranger:

stranger: anyone who does not belong in the environment in which they are found
intruder: someone who intrudes on the privacy or property of another without permission

Other hypernyms of stranger include interloper, trespasser.

stranger (noun)	intruder (noun)
anyone who does not belong in the environment in which they are found	someone who intrudes on the privacy or property of another without permission
an individual that one is not acquainted with