查询结果:

adj. 必要的,必需的;必然的;不可避免的  
n. 必需品  

拆分: ne-否定 + -cess-行走,退让→离开 + -ary形容词词尾 ⇒ 离不开的   

例:
adj.
It took me a year to get the necessary materials together. 我花了一年的时间才把所需要的资料组织好。 
It is necessary that one should obey the law. 一个人遵守法律是必要的。 
Because the company was doing more business it was necessary to expand the factory. 由于公司业务的扩大, 扩大工厂是必然的。 
n. 
He has enough money to obtain the necessaries of life. 他有足够的钱购买生活必需品。