The correct option is
D Skillful
The word 'maladroit' is characterized by clumsiness or lack of adroitness.
Option A, authoritative indicates a commanding and self confident character.
Option B, skillful refers to having or showing skill.
Option C, maladjusted refers to failing to cope with the demands of a normal social environment.
Option D, malevolent refers to having or showing a will to do harm to others.
Thus, according to the meaning, the word 'skillful' is the most different in meaning from the word 'maladroit'.