The most common and most likely answer to this crossword clue is the 9 letter word VISIONARY
I've seen this crossword clue in The Sunday Telegraph
V
I
S
I
O
N
A
R
Y
More clues leading to the result VISIONARY
Buddy explains!

The straight part
We know that "unpractical" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unpractical = visionary.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does VISIONARY mean?
VISIONARY noun- Someone who has visions; a seer
- An impractical dreamer
- Someone who has positive ideas about the future
- Having vision or foresight
- Imaginary or illusory
- Prophetic or revelatory
- Idealistic or utopian