off 英式读音[ɒf]美式读音[ɔːf]。
off，英语单词，主要用作为副词、介词、形容词、名词、动词，作副词时译为“离开；脱掉；出发，起跑；结束，取消；（电）未连接；没有；下班；减价；在剧院舞台的后面”；作介词时译为“离开；偏离；从……去掉；下班；
削价；戒除；不在；（非正式）远离；（非正式，一般是暂时）厌恶”；作形容词时译为“远离的；空闲的；（食物）不新鲜的；不能接受的；发挥失常的；（车轮等成对的物体之中）右边的；（某些体育比赛）越位的；（非正式）令人不快的；（非正式）不舒服的；
（非正式）不友好的”；作名词时译为“（非正式）起跑；（板球）击球手对面的半场；（非正式）休息日”；作动词时译为“（非正式）杀死（某人）；（非正式）离开”。
基本要点
1.off用作名词时的基本意思是“起跑线，（板球）击球手对面的半场”，主要用于非正式用语。
2.off既可用作可数名词，也可用作不可数名词。常与the连用。
3.off用作动词时的意思是“（非正式）杀死（某人）；（非正式）离开”，是非正式用语。
4.off既可用作及物动词，也可用作不及物动词。用作及物动词时，后常跟简单宾语。
单词释义
根据《柯林斯英汉双解大词典 》：
PREP If something is taken off something else or moves off it, it is no longer touching that thing. (从某物) 下来。
ADV Off is also an adverb. 下 [ADV after v]。
PREP When you get off a bus, train, or plane, you come out of it or leave it after you have been travelling on it. 下 (公车、火车、飞机等)。
ADV Off is also an adverb. 下 (公车、火车、飞机等) [ADV after v]。
PREP If you keep off a street or piece of land, you do not step on it or go there. 不在 (某街道、某地等) 上。
ADV Off is also an adverb. 不在 (某街道、某地等) 上地。
PREP If something is situated off a place such as a coast, room, or road, it is near to it or next to it, but not exactly in it. 在离 (某地) 不远处。
ADV If you go off, you leave a place. 离开。
ADV When you take off clothing or jewellery that you are wearing, you remove it from your body. (从身体上脱、摘) 下 [ADV after v]。
ADV If you have time off or a particular day off, you do not go to work or school, for example, because you are sick or it is a day when you do not usually work. 不在工作中地; 不在学习中地。
PREP Off is also a preposition. 不在工作中; 不在学习中。
PREP If you keep off a subject, you deliberately avoid talking about it. 避开 (某话题)。
PREP If there is money off something, its price is reduced by the amount specified. 减 (价) [amount PREP n]。
ADV Off is also an adverb. 减 (价)。
ADV If something is a long way off, it is a long distance away from you. 离 (某处) 远 [n/amount ADV]。
ADV If something is a long time off, it will not happen for a long time. 离 (某时) 远 [n/amount ADV]。
PREP If you get something off someone, you obtain it from them. 从 (某人那里得到) [口语] 。
词组短语
off and [口]忽然
off with （用于祈使句）去除；脱掉
off of 从
go off 离开；进行；变质；睡去
right off 立刻；马上
from off 从…离开
off and on 断断续续地，时不时地
on off 开关离合通断双位式
straight off 立即；马上
from the off [英国俚语]从头开始；从起点开始，从一开始
双语例句
A button had come off my coat.
我的外套掉了一颗纽扣。
I hacked the dead branches off.
我把枯树枝砍掉了。
I cleaned the mud off my shoes.
我刷掉了鞋子上的泥。