rational

rational, reasonable, sensible

这些形容词均有“明智的，合情合理的”之意。
rational: 指有理性的，有思维推理能力，而不是凭感觉冲动从事。
reasonable: 表示合乎情理、公正或务实。
sensible: 一般指合乎常情、切合实际的行为与思想，侧重明白事理。

名词 rational:

1. an integer or a fraction
   同义词：rational number

形容词 rational:

1. consistent with or based on or using reason
2. of or associated with or requiring the use of the mind
   同义词：intellectual, noetic
3. capable of being expressed as a quotient of integers
4. having its source in or being guided by the intellect (distinguished from experience or emotion)

1. The examiners put a premium on rational argument.
   评委们对以理服人的论据给以高度评价。
2. The quality or condition of being rational.
   合理性合乎理性的性质或状态
3. No rational person would go to work in his pyjamas.
   任何神智正常的人都不会穿着睡衣去上班。
4. Man is a rational being.
   人是有理性的生物。

ra.tion.al

adj.（形容词）
Having or exercising the ability to reason.
理性的，明智的：具有或者使用理性能力的
Of sound mind; sane.
神智健全的；头脑清晰的；正常的
Consistent with or based on reason; logical:
合理的；与理性相符或以理性为基础的：
例句：
rational behavior.See Synonyms at logical
理智的行为参见 logical

Mathematics Capable of being expressed as a quotient of integers.
【数学】 有理的，有理数的：能够变成整数之比的形式的

来源：
Middle English racional
中古英语 racional
from Old French racionel
源自 古法语 racionel
from Latin ratiôn3lis
源自 拉丁语 ratiôn3lis
from ratiô ratiôn- [reason] * see reason
源自 ratiô ratiôn- [原因] *参见 reason

【引伸】
ra.tionally
adv.（副词）
ra.tionalness
n.（名词）