1. 无能;笨拙
If you refer to someone's ineptitude, you are criticizing them because they do something with a complete lack of skill.

1. having no qualities that would render it valuable or useful

e.g. the drill sergeant's intent was to convince all the recruits of their worthlessness

Synonym: worthlessness

2. unskillfulness resulting from a lack of training

Synonym: awkwardnessclumsinessineptnessmaladroitnessslowness