What has happened to my "water pressure"?

I’m not quite sure exactly what you are describing. Did your neighbor turn on the taps and then hold his hand over the opening for a few seconds and then the water flowed after he took his hand away? If yes it is possible you have some rust or minerals stuck in the aerator.
Some questions for you:
Do other faucets work OK?
Does your outside spigot work normally?
Do you have a well or do you have town water?
Does either hot or cold flow more than the other?
Do you have a wrench so you can take off the aerator at the end of the spigot?

If it is mainly the hot water, then I would guess it is lime scale in the pipes. Where I live the water all comes from underground and is quite hard water, every 3 to 6 months you need to clean out anything water runs through, specially the hot water pipes.

If this is the problem it can be fixed with a special acid, but I would seriously advise you hire a pro to do the work. The acid that is used to clean it is so corrosive you would not believe it.

If you, as I do, have a well (a deep one in my case), you may well have grit as well as lime scale on the pipes. The hot water flow to my washing machine is very lethargic.

A quick fix for small problems is to flush the pipes with white vinegar. I dump a little down my toilets periodically.

Is there a difference between “water pressure” and water pressure?

sorry for the lack of details. I live in an apartment block. In a city. Not sure were a spigot would be? So I am connected to the main water supply. The hot water runs slightly slower. It seems that if I place both hands on the faucet to stop the water and put the taps on full it releases pressure for a moment then works for a while but not long. But it is both cold and hot water. All the taps are slow, kitchen and bathroom.

Also the toilet does not flush as great as before.

Sounds like the water pressure has dropped. That could be because of leaks in the building or under the streets. It could be because of people illegally tapping the water either in the building or before it reaches your building.

Report it to the landlord, and possibly to the water company. You live in a nation where I would imagine that water theft may be more prevalent than in the US. Also, I doubt if the infrastructure is as well maintained as it is in the US. I don’t know if there’s anything you can do about it other than to report it and hope that someone who is responsible tracks it down.

Spigot or tap(valve)

Where are you?

Was it a sudden drop? It could be a piece of debris suddenly stuck in your water meter.