warn

advise, caution, warn, admonish, counsel

动词 warn:

1. notify of danger, potential harm, or risk
2. admonish or counsel in terms of someone's behavior
   同义词：discourage, admonish, monish
3. ask to go away
4. notify, usually in advance

1. He warned us against pickpockets.
   他告诉我们要小心扒手。
2. I warned them that there might be snakes in the woods.
   我提醒他们树林里可能有蛇。
3. He warned me against going there at night.
   他警告我晚上不要到那去。

warn

v.（动词）
warned,warn.ing,warns
v.tr.（及物动词）
To make aware in advance of actual or potential harm, danger, or evil.
警告：在真实或可能的危害、危险或邪恶到来之前使知晓
To admonish as to action or manners.
告诫：对行为或礼节等的告诫
To notify (a person) to go or stay away:
通知（某人）离开或呆在一旁：
例句：
warned them off the posted property.
通知他们不要去碰登记过的财产

To notify or apprise in advance:
预告：预先通知或告诉：
例句：
They called and warned me that they might be delayed.
他们打来电话，预先告诉我他们可能耽搁一会儿

v.intr.（不及物动词）
To give a warning.
发出警告

来源：
Middle English warnen
中古英语 warnen
from Old English warnian * see wer- 4
源自 古英语 warnian *参见 wer- 4

【引伸】
warn.er
n.（名词）
<参考词汇><同义词>warn,caution,forewarnThese verbs mean to give someone notice of and put the person on guard against actual or possible danger or risk.
这些动词表示通知某人以使其对真实或潜在的危险或险情有所警觉。
Warn, the most inclusive, implies well-timed notice that causes a person to be alert, vigilant, or wary:
Warn 含义最广，它含有通知及时以使某人留神、警觉或警惕之意：
例句：
.My father was warned by the neighbors that we were in great danger. (W.H. Hudson).
.邻居告诉我父亲，我们的处境极端危险. (W.H.哈得孙）。

Caution often suggests a warning that calls for the use of circumspection or prudence,as in avoiding unpleasant consequences:
Caution 经常表示引起谨慎或小心的警告，如警告避免不良影响：
例句：
The Secretary of State cautioned that terrorism would be countered by retaliatory action.
国务卿警告说，恐怖主义将要受到报复性还击。

Forewarn intensifies the sense of advance notice:
Forewarn 强调了事先通知这一意义：
例句：
Forewarned is forearmed.
先通知的就先准备好