The most common and most likely answer to this crossword clue is the 9 letter word VIGILANTE
I've seen this crossword clue in The Daily Telegraph
V
I
G
I
L
A
N
T
E
More clues leading to the result VIGILANTE
- Unofficial law enforcer has criminal given tail
- Security guard, before following old poet, runs away
- Unofficial cop versus one GI with large stake
- Protector unofficially left when grabbed by colossus during fight
- Unofficial law enforcer poet from Rome right away topped one from Florence
- Big man about fifty tackled by rival who looks out for trouble?
- Crime-fighter mutilated evil giant
- One unofficially upholds law, leaving it in ruins
- Stupidly leaving it for unofficial policeman
- Member of unofficial force leaving it after order’s changed
Buddy explains!
The straight part
We know that "One unofficially upholds law" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one unofficially upholds law = vigilante.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 VIGILANTE mean?
VIGILANTE noun- A person who considers it their own responsibility to uphold the law in their neighborhood and often does so summarily and without legal jurisdiction.