= causative action by which humans use an iron tool to cause an object to have a thin cutting edge, in order to make it useful and effective as a tool; usually associated with aggression
to sharpen, to whet
Impact
literally: sharpened; hence: = process by which part of the human body is pierced by a sharp object; used figuratively to denote an experience of anger and bitterness
to be pierced, to be pricked
Know
literally: to pierce (someone with knowledge); hence: = causative action by which humans impart knowledge onto other humans with diligence