pon·iard 
(pŏnyərd)
(pŏnyərd)n.
A dagger typically having a slender three- or four-sided blade.
tr.v. pon·iard·ed, pon·iard·ing, pon·iards
To stab with such a dagger.
[French poignard, from poing, fist, from Old French, from Latin pugnus; see peuk- in the Appendix of Indo-European roots.]