the.com/keen
Sharp enough to cut, eager enough to bleed for it.
means Mentally sharp, intensely eager, or describing a finely honed edge or perception.
from From Old English cene, meaning bold and brave, before it pivoted to mean mentally sharp — the courage became cleverness.
Second lifeIn Ireland, keening means wailing loudly for the dead.
British slangKeen can mean almost too eager, slightly suspiciously.
Price keenSellers call cheap prices keen, meaning sharply competitive.