Removing a specific app from spotlight
Yes, you can exclude a specific application from Spotlight search results from its Privacy pane in OS X Yosemite.

Along with TextEdit I have TextWrangler and Sublime Text 2 installed under OS X Yosemite.  If in Spotlight I type text the listed order is:


TextEdit
TextWrangler
Sublime Text 2


If I go to System Preferences > Spotlight > Privacy and drag and drop the TextEdit application bundle onto the list area of the Privacy pane and close System Preferences and go back to Spotlight and type text the listed order is now:


TextWrangler
Sublime Text 2


So, just do as I did and it solves your issue.