in·sid·i·ous
adjective/ɪnˈsɪdiəs/
/ɪnˈsɪdiəs/
(formal, disapproving)- spreading gradually or without being noticed, but causing serious harm
潜伏的；隐袭的；隐伏的 - the insidious effects of polluted water supplies
供水系统污染的潜在恶果
Oxford Collocations DictionaryInsidious is used with these nouns:- threat
Word Originmid 16th cent.: from Latin insidiosus ‘cunning’, from insidiae ‘an ambush or trick’, from insidere ‘lie in wait for’, from in- ‘on’ + sedere ‘sit’. - the insidious effects of polluted water supplies