- 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
Source: Merriam-Webster Dictionary
- Submitting material that in part or whole is not entirely one's own work without proper attribution. Plagiarism is further defined as the use, without giving reasonable and appropriate credit to or acknowledging the author or source, of another person's original work, whether such work is made up of code, formulas, ideas, language, research, strategies, writing or other form(s).
Source: NPS Academic Honor Code (PDF)
You are committing plagiarism if you use content from another source without giving credit. It does not matter whether or not you intended to plagiarize.