1、意思不同
keep away意为“不接近；离开；避开等”。
keep off意为“不接近；使离开”。
2、用法不同
keep away：away是副词，其后通常与from搭配使用。
例如：Keep away from the fire! 勿靠近火炉！
keep off：off既可用作介词，也可用作副词。
例如：Animals were afraid of fire, so they made a big fire to keep wild animals off (= keep off wild animals). 动物怕火， 因此他们生起了一堆大火以防野兽接近。
扩展资料
keep与介词或副词搭配，构成动词短语。
1、keep back意为“阻止；留在后面”。如：
She sat down quietly, but she couldn't keep back her tears.
她静静地坐下来，却忍不住流下了眼泪。
2、keep together意为“在一起；动作协调”。如：
The eight men kept together during the boat race as though they were one.
赛船时，这8个人动作协调，好像一个人似的。
3、keep up意为“持续；使不低落”。如：
The noise kept up all night.
噪音整夜持续着。
4、keep up with意为“跟上；和……来往”。如：
I'm trying my best to keep up with the others in class.
我正在设法赶上班里的其他人。
5、keep...in mind意为“把……记在心里”。如：
The teacher asked us to keep these sentences in mind.
老师要我们把这些句子记在心里。
keep off; 不接近,不让接近 Keep off the grass. 勿踏草地本回答被网友采纳
keep off; 不接近,不让接近 Keep off the grass. 勿踏草地 （这里不能替用）