The most common and most likely answer to this crossword clue is the 8 letter word OVERRULE
I've seen this crossword clue in Financial Times
O
V
E
R
R
U
L
E
More clues leading to the result OVERRULE
- Veto law to do with deliveries at Lord's?
- Don't allow botanical body to admit blunder
- Reverse across line
- Veto concerning game against the French
- Set aside bowling regulation?
- Set aside mistake in cracking egg
- Disallow deliveries — pity — when crossing line
- Disallow sin in botanical body
- Reject past convention
- Past law in reverse
Buddy explains!

The straight part
We know that "Reverse" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case reverse = overrule.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 OVERRULE mean?
OVERRULE verb- To rule over; to govern or determine by superior authority.
- To rule or determine in a contrary way; to decide against; to abrogate or alter.
- To nullify a previous ruling by a higher power.
- To dismiss or throw out (a protest or objection) at a court.