hydra

 Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++hy·dra /ˈhaɪdrə/ noun  n1. → Hydra2. [countable] formalBAD BEHAVIOUR OR ACTIONS a problem that is very difficult to get rid of because it keeps returning 难以根除的祸患

Examples from the Corpus

hydra• But the regenerative powers of the corporate hydra were insidious.• He drew the sliver of light across that limb of the hydra as if slicing cheese.• Quite quickly the whole corridor filled to the brim with the substance of the hydra.nHydraRMa snake in ancient Greek stories with many heads that grow again when they are cut off 〔古希腊神话中头被斩去后会复生的〕多头蛇

hy·dra nounHydraLDOCE OnlineChineseSyllable  

Corpus very problem a is difficult that

hydra
hy‧dra /ˈhaɪdrə/ noun
1. Hydra a snake in ancient Greek stories with many heads that grow again when they are cut off
2. [countable] formal a problem that is very difficult to get rid of because it keeps returning

hydraBrE /ˈhaɪdrə/ 🔊NAmE /ˈhaɪdrə/ 🔊 nounHydra (in ancient Greek stories 古希腊神话) a snake with several heads. As one head was cut off, another one grew. In the end it was killed by Hercules. 许德拉，多头蛇（砍去一个头即长出新头，后为大力神赫拉克勒斯所杀）(formal) a thing that is very difficult to deal with, because it continues for a long time or because it has many different aspects 棘手的复杂事物；难以根绝的祸患(biology 生物) an extremely small water creature with a tube-shaped body and tentacles around its mouth 水螅