The most common and most likely answer to this crossword clue is the 10 letter word CONTRAVENE
I've seen this crossword clue in The Guardian
C
O
N
T
R
A
V
E
N
E
More clues leading to the result CONTRAVENE
- Conflict with flier featured in foreign tale
- Fail to observe Poe character in short story
- Dispute with flyer featured in short story
- Break lag facing bird inside deserted Thameside
- Criminal with bird in empty time break
- Infringe against senior clergyman over the internet
- Break from working not possessed by fearful energy
- Break veteran arranged after first of campaigns in operation
- Conservative to go briefly to north-east for break
Buddy explains!
The straight part
We know that "Fail to observe" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fail to observe = contravene.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 CONTRAVENE mean?
CONTRAVENE verb- To act contrary to an order; to fail to conform to a regulation or obligation.
- To deny the truth of something.