gatecrasher vs intruder

gatecrasher and intruder both are nouns.

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

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

gatecrasher: someone who gets in (to a party) without an invitation or without paying
intruder: someone who intrudes on the privacy or property of another without permission

Other hypernyms of gatecrasher include interloper, trespasser.

gatecrasher (noun)	intruder (noun)
someone who gets in (to a party) without an invitation or without paying	someone who intrudes on the privacy or property of another without permission