He thought it was impractical.

But, of course, that is impractical.

From Don Quixote, pursuer of lofty but impractical ideals.

So, although that would be really, really awesome, again, that's extremely, extremely impractical.

Most of them impossible, some of them impractical and one or two of them certainly immoral.

It's a little known, but brilliant, genius invention of Robert Stirling that takes the hot air engine from being somewhat impractical

But this was entirely impractical, for he was used to sleeping on his right side, and in his present state he couldn't get himself into this position.

But we have already talked about in a case like this that's very impractical, even if you tried to do it, by the time you did it your data might be stale.

This one's a little impractical wrapping a string around the earth and there's no reason to believe the moon and the earth have the same circumference, not to mention, how do we calculate the circumference of the moon?