check for leaks
Unscrew the aerator from the end of the faucet where the water comes out and clean the screen. Sediment build up slows the flow.
Possibly a pressure reducing valve installed after piping for first faucet, which would cause situation describing.
You have to undo the aerator at the end of the faucet and clean the screen or plastic water saver out. It will be plugged with sand or sediment.
Most of the newer kitchen faucets have "flow restrictors" to limit water use.
You have an old seal. Like a rubber ring in your faucet. Replace it.
Some faucets use the water pressure to open the seal after it has been released by the handle. It may be that the seal is tight and slow to move after it has been released. One other thing to check, is your water pressure ok at this faucet.
The water valve under the sink is turned off or has gone bad. It is possible that there is a blockage in the faucet itself. I'd start by ensuring that the water valve is turned off, and take the faucet apart and look for anything out of the ordinary.
Have you got two single faucets or a single lever faucet? It could be a pressure imbalance or it could just need maintenance
Turning on one faucet will cause a pressure drop at any other faucet that is running, but you say it is a "significant" drop - that implies that you have low water pressure, period. You might to consult with a plumber to see if anything can be done - if you live in a house with very old steel plumbing pipes, replacing them can make a noteworthy difference (it's not cheap, of course). Or possibly, you have an unusually low pressure system, perhaps a gravity feed system. Installing a water pump will solve any inconvenience, such as the shower almost quitting when a toilet is flushed elsewhere.
Low water pressure or cold water main undersized.
Just the same as in a house. - detach a faucet or many faucets, at one end of building and blow in air from the other end.
A Roman tub faucet does have good water pressure because it is made to do that. How good this is depends on how other brands perform in this area.