"To steal and pass off (the ideas or words of another) as one's own : use (another's production) without crediting the source. To commit literary theft : present as new and original an idea or product derived from an existing source" - Webster's Dictonary
Credit:"Plagiarism." Microsoft Word 2010 Clip Art.
Whenever you quote, paraphrase, or summarize a source, you will need to use proper bibliographic citation using in-text citation (MLA or APA citation) or footnotes (Chicago).