WordNet (r) 3.0 (2006):

dyeweed
    n 1: small Eurasian shrub having clusters of yellow flowers that
         yield a dye; common as a weed in Britain and the United
         States; sometimes grown as an ornamental [syn: woodwaxen,
         dyer's greenweed, dyer's-broom, dyeweed, greenweed,
         whin, woadwaxen, Genista tinctoria]