The import tool allows you to import you own list of keywords from meta tags, extract keywords from a URL, projects, from a text file, or by directly copy and pasting, directly into Keyword Discovery. Your keywords can then be analyzed, cross-referenced, added to projects, or used in any other way search keywords can normally be used in Keyword Discovery.
For more information on Importing Keywords:
If you need to clean up and filter your keywords before importing them, the Keyword Manger tool, accessible from the Keyword Tools menu on the toolbar includes features to Remove duplicates, Remove unwanted characters or words, Split multiple word phrases into single phrase keywords or add a new characters or words in front of or after existing keywords.
For more information on the Keyword Manager tool: