rapier

A slender, straight, sharply pointed sword (double-edged, single-edged or edgeless), designed predominantly for thrusting; used during the Renaissance period of Europe for civilian duelling

[…] In his lawless fit, Behind the arras hearing something stir, Whips out his rapier, cries ‘A rat, a rat!’ And in this brainish apprehension kills The unseen good old man.

The man beside him with the earrings and the big black case proceeded to unlock it. He took out of it two long Italian rapiers, with splendid steel hilts and blades, which he planted point downwards in the lawn.

Extremely sharp.

Cutting; employing keen wit.

John is very quick on his feet during interviews by using his rapier responses.

A surname.