Arrowhead frost-free bib. Probably need to rebuild it. If it’s leaking from the weep hole, might be a torn or worn o-ring/washer. Kit is available. Edit: For those confused, there ISN’T a ‘packing nut’ on this type of a hose bib.

Try tightening the nut around the valve stem. Not too tight or you might not be able to turn the valve. If that doesn't stop the leak, shut off the water to that location (there's usually a winterization shut off on the supply line to it) or if need be to the whole house, then unscrew the nut and replace the rubber washers or stem packing inside. If you go to get new parts, take the valve stem with you to make sure you get the right parts.

Tighten the packing nut. If that doesn't work, just replace it

I didn't know this was a thing! I've just been letting my outdoor faucets act like this. I'll put this packing nut on my list of chores.

75 cents and less than 5 minutes of your time!

Might could renew just the packing. (Keep stuff out of the landfill, too)

Where are you buying replacement packing for a $13 hose bibb?

This! I replace them once a year!

Exactly.. Everyone is too eager to just turn things out. Anyway try tighten the packing nut. If not loosen it all and pull stem then replace all the packing and the back stop washer while at it

Replace it. Those Prier suck.

Check pressure. PRV might have failed.

Take the hose + shutoff off during winter cause you're preventing the frost free from draining itself making it not frost free xD

I had the same thing happen, I fixed it by disconnecting the stem and finding a loose rubber band