To discard an item at a high velocity

A stupid person; it refers to the lack of surface area on an individual's brain. The general thought is that the more surface area (wrinkles, creases, etc.) a brain has, the smarter the person is. Conversely, a person with a smooth brain (no wrinkles) has less surface area and would therefore be stupid.

A word one may scream while propelling an object through the air at alarming speeds, heights, and etc.

An extremely expressive word that can be used in many situations.
On one end of the spectrum, "yeet" can be bellowed with a full, guttural sound whilst lobbing an object furiously to assert authority (great for water balloons and empty containers). On the other hand, "yeet" can be used gently, like the faint brush of a butterfly's wings as it crosses one's lips, as one completes a difficult task (i.e. boss in a difficult game, tough question on a math test).

n. Everyone thinks they know what it means until they realize they have no f*cking clue

To throw with mad force

Your reaction when your mum buys you some fresh crocs