Is it grammatically correct to say less than incompetent explain ineptness?

The phrase "less than incompetent" is grammatically correct, but it's not a standard phrase and might be considered awkward or confusing.

Here's why:

* "Less than" implies a scale: It suggests there's a level of competence below incompetent. This is unusual, as incompetence usually implies the complete lack of ability.

* "Ineptness" is redundant: "Ineptness" already means a lack of skill or competence.

Here are some alternatives that might be clearer and more effective:

* "Utterly incompetent"

* "Completely lacking in ability"

* "Entirely incapable"

* "Not even competent"

Ultimately, the best way to phrase this depends on the specific context and the desired tone.