AFAIK, We negate an adjective using mal-. but in the case of the word konscia, I saw somewhere in Gerda malaperis this word nekonscia.

so Why not malkonscia?

(my english is not very good, I know )

ne and mal are basicly differents. In some cases, the difference is so small that using one or other gives the same meaning. But in other cases, the difference is biger.

- mal signifies that it's the contrary of the following word
- ne signifies that its the negate of the follwing word, the following word is false, but the contrary could also be false.

Exemple :
- neamiko : someone, who we don't well know, or who is not a friend..but not necessary an enemy...we just don't care about him
-malamiko : enemy

For the word konscia, for me, both signifies the same thing (and also senkonscia^^)

Thank you so very much dear Oxymor. Now I get it

Malkonscia isn't really a word that's used, actually.

Though I would personally say that malkonscia would mean unconscious (fully unconscious, not aware of anything at all), whereas nekonscia has a broader set of meanings, it could mean either fully unconscious, or it could also mean not aware of a specific fact (fully awake and moving around, but unaware that your friend is about to come over to visit, for example)