Longman Dictionary of Contemporary English
Wiktionary
a. 1 (context not comparable English) Of a blade, such as a sword or knife, sharp on both edges. 2 (context comparable figuratively English) As dangerous for the user as the one it is used on.
WordNet
adj. capable of being interpreted in two usually contradictory ways; "double-edged praise"
Usage examples of "double-edged".
Each man bore both a short sword ensheathed at the left hip and a slim lance with a double-edged tip, more appropriate to horsemen than foot soldiers, but light and short enough to be carried easily.
SEx Doc INNOCENT, the Inquirer headline screamed in a double-edged exoneration the morning after the suit was dismissed.
When he had noted all its wonder--for to him it was a most marvellous thing made of a glittering stone such as he had never seen, that was thrice heavier than any stone, hafted with black bone as hard as walrus ivory with a knob at the end of it fashioned by rubbing down the knuckle joint, to save it from slipping through the hand, lashed about here and there with neatly finished strips of hide, double-edged and sharper than a flint flake, balancing in the grasp also--oh!
In these circumstances, the Kellogg-Briand language of peace became, rhetorically and legally, a double-edged sword: used, in the new draft constitution, to protect the emperor even as it was being unsheathed to cut down his erstwhile officers and officials.
Once again, the unifying power of the subaltern nation is a double-edged sword, at once progressive and reactionary.
No doubt the marked contrast between the neighbouring people of Nova Scotia and New England was quickly discerned by so good an observer as the author proved himself to be, while his national and partisan judgments made his characterization of the Yankee to be a double-edged sword, that cut with equal keenness the Colonist and the Democrat.
In the airport later that day I was able, fortuitously, to purchase a stainless-steel shaver with flat, double-edged disposable blades.
A loin cloth of soft leather was tied around his waist so as to serve the purpose of a belt, and through it were stuck, on the right and left sides respectively, a long double-edged knife, and a sumpitan, or blow gun, with its pouch of poisoned darts.
Her bow was hooked over her shoulder, but Askari drew a double-edged skinning knife from the buckskin sheath at her side.
The Oecumenical Council was so double-edged a weapon that it is not remarkable that the popes hesitated to grasp it in their war with the heretic.
He and Wulfgar were back to back a short distance away, the lizardman brandished a broad-bladed, double-edged sword while the dwarf held a long-hafted axe and practiced laying about him with vicious half-circle arcs.
The mercie slid the double-edged point in under the third breastplate from the top.
The rider sat astride of a saddle, as in the Butteridge machine, and he carried a large double-edged two-handed sword, in addition to his explosive-bullet firing rifle.
He wore a knee-length chainmail hauberk and steel strips on leather armguards, a plain double-edged sword at his waist.
However, if I were a Cypherpunk, I would view this kind of attention as a double-edged sword.