piercer (n.)

c. 1300 (c. 1200 as a surname), percen, "make a hole in; force one's way through; thrust through with or as with a sharp or pointed instrument," from Anglo-French perser, Old French percier "pierce, transfix, drive through" (12c., Modern French percer), probably from Vulgar Latin *pertusiare, frequentative of Latin pertusus, past participle of pertundere "to thrust or bore through," from per "through" (from PIE root *per- (1) "forward," hence "through") + tundere "to beat, pound," from PIE *tund-, from root *(s)teu- "to push, strike, knock, beat, thrust" (see obtuse). Related: Pierced; piercing.