1. Literally, to pierce one with some very small, sharp-pointed instrument or organ, especially as found on plants, insects, and sea life. Jellyfish are able to sting people with tiny harpoon-like structures along their tentacles called cnidocytes. When a honeybee stings you with its stinger, the barbed point becomes lodged in your skin, causing continued pain for you but death for the bee.

2. To present one with some charge, fine, or fee, especially one that is surprising or seems unfair. All the mechanic did was swap out a replacement part, but he stung me with an $800 repair bill. Just be aware that the airline will sting you with a hidden 10% administrative fee on top of all the other costs for your trip.