The Collaborative International Dictionary of English v.0.48:
Rapier \Ra"pi*er\ (r[=a]"p[i^]*[~e]r), n. [F. rapi[`e]re, perhaps for raspi[`e]re, and ultimately of German origin, akin to E. rasp, v.] A straight sword, with a narrow and finely pointed blade, used only for thrusting. [1913 Webster] Rapier fish (Zool.), the swordfish. [Obs.] --Grew. [1913 Webster]