The most common and most likely answer to this crossword clue is the 5 plus 4 letter word BLIND SPOT
I've seen this crossword clue in The Times
B
L
I
N
D
S
P
O
T
More clues leading to the result BLIND SPOT
- Possible Venetian spy, a source of misunderstanding?
- Additions to window over sink? Not something I can comment on perhaps
- In poker, stakes pool of money in area of ignorance
- Secures trophy, pocketing pounds? I can’t see it
- Shades grass area where vision obscured
- Possible Venetian spy misunderstood subject
- Conveniently ignored area of revolting snot build-up? Not us!
- Area unseen behind lorry is notedly difficult, initially, to see
- Unseen area in which Venetians perhaps sink?
- Area misunderstood puts learner in annoying situation, awkward position
Buddy explains!

The straight part
We know that "area of ignorance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case area of ignorance = blind spot.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.