You can hide files from Spotlight by adding them to the privacy folder within System Preferences. There is a quicker way to hide files within Mac OS X. This is to add .noindex to the end of files or folders. This is an older, but still suitable, method for hiding files. By adding this to the end of files it will tell your Mac not to index them in spotlight. It is an ad-hoc method of hiding files without using the system preferences option. This tip works for files and folders.
Hiding Files With NoIndex
This method is very simple to implement. Select the file you wish to hide and add .noindex to the end of the file name.
There must be no space between the last word of the file name and .noindex. For example “file .noindex” will not work. It must be “file.noindex”.
This word must also be before the file extension. For example it is “file.noindex.txt” not “file.txt.noindex”. This will confuse your Mac and will mac it think .noindex is the file extension.
Have a play around with the file name and see how it works. If you come across files with this extension you can remove it to have the file indexed by spotlight.