形容詞 arbitrary:

1. based on or subject to individual discretion or preference or sometimes impulse or caprice

1. An arbitrary amount of information whose beginning and end are defined or implied.
   一組任意量的信息，其起始和結束是確定的或隱含的。
2. I have no idea of what is in fashion so my choice is quite arbitrary.
   我不知道什么時興，因此我的選擇是非常隨意的。
3. Most presidents in this African country are arbitrary rulers.
   這個非洲國家的總統(tǒng)大多數是專橫的統(tǒng)治者。
4. The choice of players for the team seems completely arbitrary.
   對隊員的挑選似乎完全是主觀決定的。

ar.bi.trar.y

adj.（形容詞）
Determined by chance, whim, or impulse, and not by necessity, reason, or principle:
任意的，武斷的：由偶然、一時興致或沖動而非由必然、推理或原則決定的：
例句：
stopped at the first motel we passed, an arbitrary choice; arbitrary division of the group into halves.
在我們經過的第一個汽車旅館處停下，一種隨意的選擇；將小組分為兩等分的一時興起的分派

Based on or subject to individual judgment or preference:
專制的，專斷的：基于或遵從于個人判斷或喜好：
例句：
The diet imposes overall calorie limits, but daily menus are arbitrary.
食譜規(guī)定了總的卡路里限制，但每天的菜單可據愛好自定

Established by a court or judge rather than by a specific law or statute:
由法庭的法官而非專業(yè)法律或法官決定的：
例句：
an arbitrary penalty.
判決的刑罰

Not limited by law; despotic:
不受法律限制的；專制的：
例句：
the arbitrary rule of a dictator.
獨裁者的專制統(tǒng)治

來源：
Middle English arbitrarie
中古英語 arbitrarie
from Latin arbitr3rius
源自 拉丁語 arbitr3rius
from arbiter arbitr- [arbiter]
源自 arbiter arbitr- [仲裁者]

【引伸】
ar.bitrar.ily
ar.bitrar.iness
n.（名詞）
<參考詞匯><同義詞>arbitrary,capricious,whimsicalThe central meaning shared by these adjectives is .determined by or arising from whim or caprice rather than judgment or reason.:
這些形容詞共有的中心意思是.由沖動或奇想而非判斷力或推理決定或得出的.：
例句：
an arbitrary decision;
一時興起的決定；

例句：
a capricious refusal;
忽發(fā)奇想的拒絕；

例句：
the butt of whimsical persecution.
異想天開迫害的對象。