dag·ger 
(d
ăg
ər)
n.1. A short pointed weapon with sharp edges.
2. Something that agonizes, torments, or wounds.
3. Printing a. See obelisk.
b. A double dagger.
Idiom: look daggers at To glare at angrily or hatefully.
[Middle English daggere, alteration of Old French dague, from Old Provençal dague or Old Italian daga, both perhaps from Vulgar Latin *dāca (ēnsis), Dacian (knife), from feminine of Latin Dācus.]