【Question】What’s the meaning of the word molly as “Holly Molly”? Is this an old-fashioned expression?

Question

【Question】What’s the meaning of the word molly as “Holly Molly”?  Is this an old-fashioned expression?

Answer

It’s an exclamation phrase, you use it the same way you use “oh my God” “wow” etc

Answer

Holly Molly is used to show that you think something is surprising. In a verbal conversation it stands for an "exclamation"❗
The first use of this phrase is recorded to be as old as the end of 18th century or the beginning of the 19th century.