The most common and most likely answer to this crossword clue is the 6 letter word ABLAZE
I've seen this crossword clue in The Sunday Telegraph
A
B
L
A
Z
E
More clues leading to the result ABLAZE
- A bishop with zeal for reform is extremely fiery
- Lamb done evenly — veg is burning
- A jacket almost on fire
- A short jacket, brightly coloured?
- Large street map in Lincoln’s brightly lit
- Excited bishop in a lounge
- Idle Jack leads, fuming
- Sufficiently prepared to cover central part of maze that’s on fire
- Bright sort of seaman entraps extreme characters
- Sailor’s lounge on fire
Buddy explains!

The straight part
We know that "burnt" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case burnt = ablaze.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 ABLAZE mean?
ABLAZE adjective- Burning fiercely; in a blaze; on fire.
- Radiant with bright light and color.
- In a state of glowing excitement or ardent desire.
- On fire; in a blaze, gleaming.
- Lit up brightly and with color.
- In a state of glowing excitement or ardent desire.