bookmarker vs marker

bookmarker and marker both are nouns.

Word	Noun	Adjective	Verb	Adverb
bookmarker	Yes	No	No	No
marker	Yes	No	No	No

As nouns, marker is a hypernym of bookmarker; that is, marker is a word with a broader meaning than bookmarker:

bookmarker: a marker (a piece of paper or ribbon) placed between the pages of a book to mark the reader's place
marker: some conspicuous object used to distinguish or mark something

bookmarker (noun)	marker (noun)
a marker (a piece of paper or ribbon) placed between the pages of a book to mark the reader's place	some conspicuous object used to distinguish or mark something
	a writing implement for making a mark
	a distinguishing symbol