The English synonyms for this are quite interesting. You have 'devil's darning needle', 'horse stinger', 'eye poker', 'snake doctor', and 'eye snatcher', among others. Now it's getting interesting.
Why 'devil's darning needle'? Apparently there's a superstition that if a child told lies or an adult cursed, the dragonfly would stich up his or her eyes, lips, and ears. o_O
In Finnish, we have Sudenkorento that comes from susi= wolf + korento=fly. Korento has an archaic meaning of "pole," too, maybe referring to the shape of a dragonfly's body.
I guess we found them creepy too, because other words for sudenkorento include 'pirunpuntari' (the devil's scales, apparently they'd weigh you when they fly over your head, and something horrible would happen if you didn't measure up), and there's a story that if you fall asleep outside, the dragonfly will stich up your eyes. Another Finnish legend says that a dragonfly will steal a hair off your head and hide it in a tree stump, and when the stump rots, you die. Fun stuff.
In French, dragonfly is called une libellule, from the Latin word for level, or scales. Maybe because it hangs it the air, perfectly level?
Swedish has 'trollslända' meaning witch's spindle, and 'blindsticka' that refers to sticking out eyes. So the Swedish probably aren't fans of the dragonfly, either.
German has 'Teufelsnadel' (Devil's needle) and 'wasserhexe' (water-witch).
At least in Japanese, the dragonfly 'tombo' is appreciated: I remember seeing a Samurai helmet with the image of a dragonfly on it.
The scientific name is 'odonata', from the Greek word for teeth, referring to their mandibles.
So there we have it. Anything to add? Tell me in the comments.
Karjalainen, Sami: "Suomen sudenkorennot" (Tammi, 2002)