"Most concocted" refers to something that has been falsely created or made up. The antonyms for this word would be genuine, authentic, real, legitimate, sincere, honest, and truthful. These antonyms signify that something is not exaggerated or fabricated, but rather exists in its purest form. For instance, one could say that a genuine friendship does not require any pretense or falsehoods. An authentic piece of art is one that is not replicated or copied. Similarly, a sincere apology is one that stems from true remorse and not just a desire to reconcile. Therefore, when describing something that is not concocted, using words such as authentic, genuine, and sincere will be appropriate.