You need to step back and see if you actually understood what you are asking. For example, ask yourself "What is an apple?" and see if you can answer this. Then look at the answer you gave yourself on something that you think you know.
You will find that your answer will include descriptions such as "It is a fruit" (which is really a classification of the object), "It can be eaten", "It looks like this" (accompanied by a number of pictures of different types of apples), "It tastes like... an apple" (which assume that others understand and have a reference point to what an apple should taste like), etc... etc.
In other words, all you can give are ... drum roll... DESCRIPTIONS of the PROPERTIES of an apple.
What an object is is nothing more than a series of its properties and descriptions. So what you ask "What is X?", we have no other abilities than to describe to you the properties and characteristics of X.
Unfortunately, based on how you asked about energy in this thread, it appears as if you are seeking something beyond that, and frankly, something that doesn't really exist based on how we understand things. Asking "What is energy?" will inevitably results in us giving you all the properties and description of energy based on the physics of it. It is not just one description. It is a series of description, just like the apple.
We have had numerous threads in this forum asking for the same thing. You never responded to the question on if you've done any search.
Zz.
