The most common and most likely answer to this crossword clue is the 6 letter word ULSTER
I've seen this crossword clue in Financial Times
U
L
S
T
E
R
More clues leading to the result ULSTER
- Bad result for part of Ireland
- Irish region taking part of Istanbul's territory
- Mogul’s territory includes historically trouble province
- Paul’s terylene-lined coat
- Coat brings strange result
- Irish quarter in turmoil as result
- Length in 17’s new coat
- Coat in Margaret’s luggage facing up
- What’s hidden by mogul’s terrific old coat
- Powerful steroids hidden in coat? Quite the opposite!
Buddy explains!

The straight part
We know that "coat" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case coat = ulster.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 ULSTER mean?
ULSTER noun- (clothing, men's attire) A long, loose overcoat made of wool or other rough material, often called a greatcoat, which sometimes features an attached shoulder cape covering the back and sleeves, and which can sometimes be buttoned in front.