You lost a neutral somewhere between that outlet and the panel.
The hot wire reads "hot" because you did not lose the hot; it really is hot.
The neutral reads "hot" because either there, or downline, there is at least one load plugged into the receptacle. This load connects the neutral to the hot, making the neutral hot too.
Follow the outlet chain back toward the main panel and find the first place it is dead (nearest to panel) and last place it still works (farthest from panel). Then disassemble and check both those places. The problem will be there.
The usual cause is a "back stab". Get rid of those.

This is not an emergency, because neutral is considered a conductor and is carefully insulated the same as a hot -- now you see why. On the other hand, if someone was bootlegging ground, this would be super bad news.
"How can the load pull the neutral up to 120V? Normally it drops (reduces) the voltage from 120V to zero." That's true, the load limits current with a fairly high resistance However, the circuit is broken so zero current is flowing. What happens in that case? Ohm's Law tells the tale:
E = I R
E (Voltage drop) = I (current in amps) x R (resistance in ohms)
Normally the load flows, say 2 amps across 120V, so E=120, I=2 and R =
120 = 2 * R
R is 60 of course, and that is a physical characteristic so it won't change. But with the broken circuit, current is zero, so look what happens to voltage drop:
E = 0 * 60
That's right, E is 0, so the voltage drop between the load's hot and neutral will be zero. Since hot is 120V, so then must neutral.