Vincetoxicum negrum vin·ce·to·xicumnegrum uncommon noun 1. twining vine with hairy foliage and dark purplish-brown flowers Synonymsnegro vineVincetoxicum hirsutumVincetoxicum negrum Related words Broader terms vine Parts Vincetoxicum WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.