The most common and most likely answer to this crossword clue is the 6 letter word ARDOUR
I've seen this crossword clue in The Sunday Telegraph
A
R
D
O
U
R
More clues leading to the result ARDOUR
- Enthusiasm is more exhausting, as Cockneys may say
- Hard tour: each heading off, showing great enthusiasm
- Passion of artist turning grim
- Fire a religious leader that’s gloomy
- Heat can make a run grim
- Passion‘s audibly more macho in the East End
- Passion in letter unyielding
- Revolutionary artist with stern passion
- Increasingly difficult for Eastender reporting fire
- Enthusiasm for combat is diminished – it’s grim
Buddy explains!
The straight part
We know that "Passion" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case passion = ardour.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 ARDOUR mean?
ARDOUR noun- Great warmth of feeling; fervor; passion.
- Spirit; enthusiasm; passion.
- Intense heat.