Source : Webster's Revised Unabridged Dictionary (1913)

Gypsywort \Gyp"sy*wort"\, n. (Bot.)
   A labiate plant (the {Lycopus Europ[ae]us}). Gypsies are said
   to stain their skin with its juice.

Source : WordNet®

Lycopus europaeus
     n : hairy Eurasian herb with two-lipped white flowers [syn: {gipsywort},
          {gypsywort}]