The most common and most likely answer to this crossword clue is the 10 letter word UNDESIGNED
I've seen this crossword clue in The Times
U
N
D
E
S
I
G
N
E
D
Buddy explains!
The straight part
We know that "It’s not intended" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it’s not intended = undesigned.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 UNDESIGNED mean?
UNDESIGNED adjective- Not designed, not intended.
- Not designed, not drawn or planned before being made.