General lack of skill:
* Inexperienced: This emphasizes a lack of practice or exposure to the skill.
* Unskilled: This is a blunt and direct way to say someone lacks the ability.
* Novice: This implies someone is new to the skill and still learning.
* Amateur: This describes someone who engages in a skill for pleasure rather than professionally.
* Unqualified: This highlights that someone is not suited or competent for a particular task.
Specific limitations:
* Inept: This suggests someone is clumsy or awkward in their execution of the skill.
* Inefficient: This implies someone is slow or wasteful in their approach to the skill.
* Rudimentary: This describes a basic or elementary understanding of the skill.
* Clumsy: This focuses on physical awkwardness or lack of grace in performing the skill.
* Fumbling: This emphasizes making mistakes or struggling to execute the skill properly.
Negative connotations:
* Unworthy: This suggests someone is not good enough or does not meet expectations.
* Inferior: This implies someone is significantly worse than others in performing the skill.
* Incompetent: This is a strong word that suggests a complete lack of ability.
The best word to use will depend on the specific situation and the level of formality you desire.