How do I fix this leak?

[ghoul31]

This is under my sink
Its has a very slow drip


https://drive.google.com/file/d/1PRWVNNLZG2TEinyJg2qvO4cqRTgFXQAy/view

 

[Matt30]

If it's not in use right now the quickest and cheapest option would be to get a 3/8 compression nut and 3/8 compression plug. If it's never going to be used the best option would be to eliminate the valve and solder a 1/2" copper cap on the copper.

 

[Geofd]

if the brad name is brass craft you can get a rebuild kit its just 2 washers
one goes under the big chrome nut the other pushes onto the back of the stem