James_Dale suggested this particular use of the synonym tool combined with the -(target keyword) earlier. It's fascinating to see what broad matching may now be looking for.
(It seems that one of my keywords might be enhanced by a mental health charity - needless to say that my keyword has nothing to do with mental health.)
I suggest you do what I have done, and pump every keyword into Google using this syntax, and print it out to get a record of these bizarre associations for future reference before this hole is closed also.
Note that the Adwords presented do not change - despite the exclusion of the main keyword.
Note secondly that if you use a query of this type, and no results are forthcoming - you'll probably find yourself back in the SERPs!