Incapable

[Sarah]

Unqualified or disqualified, in a legal sense; as, a man underthirty-five years of age is incapable of holding the office ofpresident of the United States; a person convicted on impeachment isthereby made incapable of holding an office of profit or honor underthe government.

[Sarah]

Not capable (of doing something); unable

Not having the necessary ability, qualification, or strength to perform some specified act or function

[Donald Trump]

Unable to do or achieve (something)