What is the definition of the prefix for amoral

Having or showing no concern about whether behavior is morally right or wrong

The definition of amoral is lacking a moral sense; unconcerned with the rightness or wrongness of something.

the meaning of the prefix "a" is simply making the word negative or opposite - lacking something. for example, moral is positive but when you add the prefix "a" it means that you lack morals, it becomes negative and the opposite of moral