To discard an item at a high velocity

Yeet is a versatile word that can be used as an exclamation, a verb, or even a noun.

As an exclamation it can be used to express excitement, usually happily but also nervously. (See Ex. 1)
It can also be used as an exclamation of victory. (See Ex. 2)
Or as a battle cry or focus-shout while throwing or hitting something, like "HIII-YA". (See Ex. #3)

When in its verb form it has different tenses with different spellings, like any other verb.
(Present) I yeet
(Past/Imperfect) I was yeeting
(Past/Perfect) I yote
(Pluperfect) I have yought
(Future) I will yeet
(Future perfect) I will have yought

As a noun, 'a yeet' is the action of yeeting. Yeet can also be a feeling or emotion, usually like an adrenaline rush. (see Ex. 1)

The word has a distinct feel, and power to it. To yeet is to give your full power and soul to an action you're doing. While many believe yeet to be a fairly new concept, it has been around for centuries. Think back to the berserker warriors. They would be so immersed in pushing all their power into their attack that they wouldn't even register pain, or go into shock, until long after a regular fighter would have passed out. They were true yeeters. A more modern example is the common use of warp speed in science fiction. It's interstellar yeet. The word 'yeet' is really all that is new about this concept, and it is a very useful word indeed.

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

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).

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

Your reaction when your mum buys you some fresh crocs

1) to throw something wildly, defying Newton's laws of motion

2) an exclamation commonly said by Americans while yeeting.