The most common and most likely answer to this crossword clue is the 8 letter word MECHANIC
I've seen this crossword clue in Financial Times
M
E
C
H
A
N
I
C
More clues leading to the result MECHANIC
- Engineer possessed round mirror with no base
- Miles before chicane, broken down – one’s help’s required
- Chance I’m upsetting one enrolled in services?
- Worker ludicrously busy round English church
- Engineer in charge pursues blokes drinking tea
- One gets car to start after machine breaks down
- Central heating in 22 busted? One’ll fix it
- One employed by F1 team, male, by newly-built chicane
- Repairman takes chance — I’m off
- Garage worker tuned machine to go over a hundred
Buddy explains!

The straight part
We know that "one enrolled in services" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one enrolled in services = mechanic.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 MECHANIC mean?
MECHANIC noun- A manual worker; a labourer or artisan.
- Someone who builds or repairs machinery, a technician; now specifically, someone who works with and repairs the mechanical parts of a motor vehicle, aircraft or similar.
- A device, command, or feature which allows someone to achieve a specific task.
- A hit man.
- Mechanical; relating to the laws of motion in the art of constructing things
- Of or relating to a mechanic or artificer, or to the class of artisans; hence, rude; common; vulgar; base.