something that you cannot see clearly

If I don't wear my glasses, everything is just a blur. 如果不戴眼镜，我看任何东西都是模糊的。

something that you cannot remember or understand clearly

It all happened so long ago that it's just a blur to me now. 这件事发生在很久以前，我现在记不清了。

The last few days seem to have gone by in a blur. 过去几天似乎是在恍恍惚惚中度过的。

to (make something or someone) become difficult to see clearly

As she drifted into sleep, the doctor's face began to blur and fade. 当她渐渐入睡时，医生的脸开始模糊，渐渐消失了。

to make the difference between two things less clear, or to make it difficult to see the exact truth about something

This film blurs the line/distinction/boundary between reality and fantasy. 这部电影模糊了现实与幻想的界限。