OneLook.com: An editor’s best friend
Why not let the power of the internet’s search algorithms do your spell-checking for you?
OneLook.com looks up a word for you in many online dictionaries all at once. So, for example, you’ll see that “copy editor” shows up in 17 general dictionaries, one art dictionary, and one computing dictionary. Now look up “copyeditor,” which turns up in seven general dictionaries. Finally, look up “copy-editor,” which appears in just one general dictionary. So based on those results, you can glean that the preferred spelling is “copy editor.”