erratic

形容词 erratic:

1. having no fixed course
   同义词：planetary, wandering
2. liable to sudden unpredictable change
   同义词：fickle, mercurial, quicksilver
3. likely to perform unpredictably- Osbert Lancaster
   同义词：temperamental

1. An empty-headed, silly, often erratic person.
   古怪的人傻的、愚蠢的并且通常很古怪的人
2. This clock is rather erratic.
   这个钟不太准。
3. Deliveries of goods are erratic.
   不按规定送货。
4. The singer gave an erratic performance.
   演唱者未唱出水平。

er.rat.ic

adj.（形容词）
Having no fixed or regular course; wandering.
飘忽不定的：没有固定的或规律性的行踪；游荡
Lacking consistency, regularity, or uniformity.
无规律的：缺乏连续性、规律性或一致性
Deviating from the customary course in conduct or opinion; eccentric:
古怪的：在行为与观点上与习惯的作法偏离；偏执的：
例句：
erratic behavior.
古怪的行为

来源：
Middle English erratik
中古英语 erratik
from Old French erratique
源自 古法语 erratique
from Latin err3ticus
源自 拉丁语 err3ticus
from err3re [to wander] * see ers-
源自 err3re [漫游] *参见 ers-

【引伸】
errat.ically
adv.（副词）
errat.icism