The most common and most likely answer to this crossword clue is the 12 letter word UNCONSIDERED
I've seen this crossword clue in The Guardian
U
N
C
O
N
S
I
D
E
R
E
D
More clues leading to the result UNCONSIDERED
Buddy explains!
The straight part
We know that "ignored" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ignored = unconsidered.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 UNCONSIDERED mean?
UNCONSIDERED adjective- Not considered.