ex libris vs sticker

ex libris and sticker both are nouns.

Word	Noun	Adjective	Verb	Adverb
ex libris	Yes	No	No	No
sticker	Yes	No	No	No

As nouns, sticker is a hypernym of ex libris; that is, sticker is a word with a broader meaning than ex libris:

Other hypernyms of ex libris include gummed label, paster.

ex libris (noun)	sticker (noun)
a label identifying the owner of a book in which it is pasted	a short knife with a pointed blade used for piercing or stabbing
	an adhesive label
	a particularly difficult or baffling question or problem
	a small sharp-pointed tip resembling a spike on a stem or leaf