Synonyms for Parasitical (same or very similar meaning)
WordNet sense 1 (relating to or caused by parasites):
parasiticWordNet sense 2 (of plants or persons; having the nature or habits of a parasite or leech; living off another):
bloodsucking, leechlikeWordNet sense 3 (not independent):
dependentFrom the ODE community, based on WordNetadd/edit