How to access Greek symbols on macOS from a basic keyboard without copy/paste?
In the top left-hand corner of the Character Viewer, there’s a gear icon. The first option is “Customise List…”.

This gives you a selectable list of all the character sets available in the sidebar. If you scroll down, you’ll find Greek as one of the options:



I don’t have a Mavericks machine to hand to check, but I’m fairly sure this feature existed before Yosemite.