toxic,poisonous,virulent,noxious有何区别

toxic

1.Of, relating to, or caused by a toxin or other poison:
有毒的：（有关）毒素或其他毒物的，或由此造成的：
a toxic condition; toxic hepatitis.
中毒状况，中毒性肝炎

2.Capable of causing injury or death, especially by chemical means; poisonous:
能够造成伤害或死亡的，尤指通过化学方法；有毒的：
food preservatives that are toxic in concentrated amounts; a dump for toxic industrial wastes.See Synonyms at poisonous
浓缩后有毒的食物防腐剂；有毒工业废料的临时堆积所参见 poisonous
n.（名词）
A toxic chemical or other substance.
有毒的化学品或其它物质

poisonous

1.Having the capability of harming or killing by or as if by poison; toxic or venomous.
有毒的：通过或好象通过毒药具有伤害或杀死的能力的；有毒的或剧毒的

2.Containing a poison.
含毒药的

3.Marked by apparent ill will:
恶毒的，有恶意的：带有明显的恶性意向的：
“poisonous hate . . . in his eyes”(Ernest Hemingway)
“恶毒的仇恨…在他的眼中”(欧内斯特·海明威)

virulent

1.Extremely infectious, malignant, or poisonous. Used of a disease or toxin.
剧毒的，致命的