It is possible to restrict access to Word documents so they cannot be printed. And although this feature is not included in all versions of Microsoft Word, there are other ways to prevent people from printing your documents.
If you use Microsoft Office Ultimate, Office Professional Plus or Office Enterprise, you can prevent your Word files from being printed. Click on the "Office" button, click on "Prepare" and then click "Restrict Document." One of the options will be to prevent printing. Other versions of Microsoft Office do not have the "Restrict Document" feature and so don't allow you to prevent your document from being printed.
If you don't have Office Ultimate, Professional Plus or Enterprise, you may still be able to lock your document. Export it as a PDF file (this is built into the Mac operating system and is available through add-on programs in Windows). Open the PDF in Adobe Acrobat or another PDF editing program. These PDF programs let you restrict documents so they can be viewed but not printed.
It is impossible to completely prevent people from printing a document. Even if the document is locked, if they can see it on their screen, they can use a screen capture program to print each page. But setting restrictions in Word or Acrobat will certainly make it more difficult for someone to print your document.