| | Hardly versus Barely
I came across this paragraph which I had to complete with hardly or barely:
"Building a hotel in the treetops is _______ a new idea, but the concept has blossomed; today you’ll find them everywhere from Massachusetts to China."
Hardly is the correct answer, but I don't understand the reason why Barely is not correct as the dictionary says that hardly and barely are synomyms.
Thank you in advance for your help.