functional

形容词 functional:

1. designed for or capable of a particular function or use
2. involving or affecting function rather than physiology
3. relating to or based on function especially as opposed to structure
4. fit or ready for use or service
   同义词：usable, useable, in working order, operable, operational
5. designed for or adapted to a function or use
6. (of e.g. a machine) performing or capable of performing
   同义词：running, operative, working

1. The set of rules governing the operation of functional units of a communication system that must be followed if communication is to be achieved.
   管理某一通信系统的功能部件操作的一组规则，如果要实现通信，必须遵循这些规则。
2. The functional changes associated with or resulting from disease or injury.
   病理生理异常与疾病或伤害有关的生理变化或由其引起的生理变化
3. I'm hardly functional if I don't get eight hours' sleep!
   我要是不睡上八个小时就无法工作。

func.tion.al

adj.（形容词）

Of or relating to a function.
职责的：有职责的或与职责有关的
Of, relating to, or indicating a mathematical function or functions.
函数的：一个或多个数学函数的、与此有关的或精于此的
Designed for or adapted to a particular function or use:
实用的：适应某种功能或用途的：
例句：
functional architecture.
实用建筑

Capable of performing; operative:
有功能的；在起作用的：
例句：
a functional set of brakes.
性能良好的刹车系统

Pathology Involving functions rather than a physiological or structural cause.
【病理学】 机能的：由功能方面的原因而不是心理或构造原因引起的

【引伸】
func.tional.ity
func.tionally
adv.（副词）