The antonym for the word "being skillful" can be "unskilled." If someone is unskilled, they lack the necessary abilities, knowledge, or experience to perform a particular task or function. Being unskilled usually leads to inadequate results and frustration. Another antonym can be "inept," indicating that one is not capable of doing something correctly or efficiently. An inept person often makes mistakes and lacks coordination or dexterity. The opposite of skillful can also be "clumsy," indicating a lack of grace, poise, or coordination. A clumsy person may be uncoordinated and careless, resulting in accidents and errors. So, being unskilled, inept, or clumsy can be antonyms for the word "being skillful.