There are plenty of times in Hitman 2 where you’re going to need to get rid of your weapon quickly. When needing to go through a pat down or frisk, having a concealed weapon on you is a good way to draw unneeded attention. To avoid this you can quickly drop weapons in Hitman 2 to avoid detection.
To drop weapons that you are holding you can press down on the d-pad. Agent 47 will drop the weapon he is holding at his feet. This will not drop all weapons in your inventory, just the weapon that you are currently holding. Pressing down on the d-pad not only works for weapons, it drops any items that you are holding.
Be careful though, if someone sees you drop a weapon, like a gun, they will report you and make you a hunted target. Before entering any checkpoints or security areas which require you to be frisked make sure to drop weapons in an area where they will not be found.