I have a number of duplicate or synonym keywords that I am trying to clean up. For example Tree and Trees. I filter my large keyword list using the filter line under keyword list. So if I put in a filter of Tree I get the keywords in my heirarchy that include Tree, Trees, Maple Tree, etc. So far so good. But it also returns things like Street, or Main Street, or Streetcar.
Is there a way to look for only tree or trees without finding street? I have the main keyword as trees with a synoym of tree but if i filter using tree I run into this problem.
There's nothing you can do using the Filter Keywords box in the Keyword List panel. However, you could export your keyword list as a text file by doing the menu command Metadata > Export Keywords. Then search the text file using your favorite text editor.
Use a smart collection: Keywords contain word tree. That will catch all images with keyword 'tree', but not 'street' or anything else that contains 'tree' as part of a larger word.
Oops, forgot something: Then after you have selected the smart collection, activate the metadata filter and the keyword list in that filter will now only show the 'tree' keywords, so you can examine them for double keywords. You will still have to select them in the keyword list panel to change them, of course.
If a text search is getting confused by multiple similarly spelled keywords, you can instead click next to a particular entry in the keywords list. This works even when identically spelled sub-keywords occur multiple times in that list: LrC can tell those apart, also they will appear distinguishably in the keywording panel, because of their varying parent keywords.
Another tactic is to temporarily rename a given keyword to include some unique string of characters - preventing any possible ambiguities, just while sorting things out. Then change this keyword's name back afterwards.
The Keywording panel has various display modes to help review what is going on with the actual images, the keywords' synonyms and their exportable / non exportable options.