meaning of 'sweep' in 'the second hand doesn't sweep'

[Shawn]

It's from a movie:

- One thing.
- Your watch.
- Is it real?
- Oh, no. It's a fake. I got it in Thailand.The second hand doesn't sweep.

What does "sweep" here mean?

[Narayanan Krishnaswamy]

The second hand doesn't sweep.

The second hand -the hand that shows the seconds. It goes round the dial once a minute.
So it is not working.
Sweep- not moving or going round.

[Shawn]

Thank you so much!
I thought the watch was a used one(2nd hand). I misunderstood.