Deleting windows font which were copied from my bootcamp partition
You can turn them off in Font Book without deleting. Open the Font Book app in your applications, scroll down until you find the troublesome font and right click/secondary click on it and select "disable font".

Alternatively, problems can often arise if you have duplicate fonts like where osx has installed both the windows fonts and it's own fonts. In this case you could also try right clicking and selecting "resolve duplicates".