Scholarly, refereed and peer-reviewed can refer to a lot of things and which your professor will want is going to vary. Always refer to your syllabus or the assignment itself to determine what will fit your needs. If a professor is going to nitpick they will generally be more concerned that your sources are peer-reviewed.
Refereed and peer-reviewed are interchangeable. These are articles or studies which are looked over before publication by scholars in that field of study. If they make it to publication that means they got the stamp of approval from one or more scholars in that field! All refereed/peer-reviewed sources are scholarly in nature. Only articles/journals are peer reviewed, books are not.
Scholarly materials are written by experts in the subject matter for academic or research purposes. They are published by a professional association or an academic institution and may or may not be peer reviewed. Books can be scholarly as can journals.
How do I tell if a journal is peer-reviewed/refereed or scholarly?
How do I tell if a book is scholarly?
Cosbrary 