The most common and most likely answer to this crossword clue is the 7 letter word STETSON
I've seen this crossword clue in The Guardian
S
T
E
T
S
O
N
More clues leading to the result STETSON
- Cowboy gear - don't change it, young man
- Hat — no as-you-were instructions when it's back to front
- Running tests on hat
- Paradigm of western dress? Don’t change it, sunshine
- Don’t strike boy in hat
- Don’t change this boy’s headgear
- Hat collections being worn, including first of trilbies
- Relative takes a bit of tweed for top of pillbox hat
- Don’t change this lad’s headgear
- Instruction to keep writing on relative’s hat
Buddy explains!

The straight part
We know that "Hat" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case hat = stetson.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 STETSON mean?
STETSON noun- A type of felt hat with a wide brim, typically worn by cowboys.