Holy Moley Meaning

(idiomatic, dated, humorous or euphemistic) An expression of surprise

Example: 1892, Nathaniel Gould, Running it off; or, Hard hit[1]:
  "Whew !" he whistled, softly; "that's curious. Same name as the lady at our place. Suppose he should be her husband. Holy moley, what a game. I've made a discovery.