The definition of impractical is not useful, or is not efficient.
An example of something impractical is a two-door car for transporting eight people.
not practical; specif.,
- not workable or useful; impracticable
- not handling practical matters well
- given to theorizing; idealistic
- Unwise to implement or maintain in practice: Refloating the sunken ship proved impractical because of the great expense.
- Incapable of dealing efficiently with practical matters, especially finances.
- Not a part of experience, fact, or practice; theoretical.
- Impracticable. See Usage Note at impracticable.
- im·prac′ti·cal′i·ty , im·prac′ti·cal·ness
- Said of people, theories, philosophies, etc.
From im- + practical