The most common and most likely answer to this crossword clue is the 8 letter word LIVERIES
I've seen this crossword clue in The Daily Telegraph
L
I
V
E
R
I
E
S
Buddy explains!

The straight part
We know that "uniforms" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case uniforms = liveries.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 LIVERIES mean?
LIVERIES noun- Any distinctive identifying uniform worn by a group, such as the uniform worn by chauffeurs and male servants.
- The whole body of liverymen, members of livery companies.
- The paint scheme of a vehicle or fleet of vehicles.
- A taxicab or limousine.
- The delivery of property from one owner to the next.
- The writ by which property is obtained.
- The rental of horses or carriages; the rental of canoes; the care and/or boarding of horses for money.
- A stable that keeps horses or carriages for rental.
- An allowance of food; a ration, as given out to a family, to servants, to horses, etc.
- Release from wardship; deliverance.
- A low grade of wool.
- Outward markings, fittings or appearance
- To clothe.