With the new search engine used by Inrecruiting you can search for candidates within your DB using not only primary keywords, but also their synonyms.
You can set up a list of Synonyms by clicking System Settings > Customisable fields> General > Synonyms.
You can now make a text search within the Keyword field to verify whether or not a keyword is present, and if you do not already have results, you can add the desired synonyms by clicking the button Add/Modify Synonyms.
Simply enter the Keyword's Synonyms to let them be included in Search.