copy editor vs copyreader

copy editor and copyreader both are nouns.

Word	Noun	Adjective	Verb	Adverb
copy editor	Yes	No	No	No
copyreader	Yes	No	No	No

As nouns, copy editor and copyreader are synonyms defined as:

Other synonyms of copy editor include text editor.

copy editor (noun)	copyreader (noun)
an editor who prepares text for publication	an editor who prepares text for publication