from The American Heritage® Dictionary of the English Language, 4th Edition
- interj. Used to express mild surprise, amazement, or enthusiasm.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- interj. (dated) Expression of surprise or annoyance.
- interj. "Why should I care?"; so what?
- adj. very good, impressive.
Alteration of Jesus. (Wiktionary)
Another substitute word for God is gee, though gee whiz and gee whillikers! are ways of not quite saying “Jesus.”