The most common and most likely answer to this crossword clue is the 8 letter word VANGUARD
I've seen this crossword clue in The Guardian
V
A
N
G
U
A
R
D
More clues leading to the result VANGUARD
- Person keeping eye on commercial vehicle, perhaps, in front
- Wagon train official in front
- Front of vehicle seen on screen
- Railwayman taking over his place in front
- Tsar not initially having a person keeping watch in front
- Leading group, security for a Black Maria?
- Most of ships returned to protect front
- One removed by conceited sentry in leading party
- Vehicle transporting a drug is at front
Buddy explains!
The straight part
We know that "front" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case front = vanguard.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 VANGUARD mean?
VANGUARD noun- The leading units at the front of an army or fleet.
- (by extension) The person(s) at the forefront of any group or movement.