The blunt edge of “knife”
The word knife came up in one of the recent comments. I have spent so much time discussing sharp objects (adz, ax, and sword) that one more will fit in quite naturally. The word that interests us today turned up in late Old English (cnīf) and is usually believed to be a borrowing of Old Norse knífr (both ī and í designate a long vowel, as in Modern Engl. knee)