Thanks for your help and your replies. I wasn't planning to use the word in the archaic sense, but rather to acknowledge in passing (one sentence in a 350-page non-fiction book) the existence of this archaic sense in order to make a larger point. But I won't do even that much if I can't find any doc...

I was wondering if someone could help me with a question that relates to a passage in a book I'm currently writing. It had always been my understanding that the phrase "glancing blow" had, perhaps a century ago, meant the opposite of what it means today -- in other words, that it meant at ...