The Greek word ἅγιος (hagios, that we also use for "holy") just means "to set apart", "different".
The fundamental (core) meaning of 40 (hágios) is "different" – thus a temple in the 1st century was hagios ("holy") because different from other buildings (Wm. Barclay). In the NT, 40 /hágios ("holy") has the "technical" meaning "different from the world" because "like the Lord."
[40 (hágios) implies something "set apart" and therefore "different (distinguished/distinct)" – i.e. "other," because special to the Lord.]
Source: http://biblehub.com/greek/40.htm
Loses most of the magic when you strip away the WTS interpretation, doesn't it?!