The most common and most likely answer to this crossword clue is the 6 letter word INGLES
I
N
G
L
E
S
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The straight part
We know that "fires" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fires = ingles.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 INGLES mean?
INGLES noun- An open fireplace.
- A catamite.
- A paramour; a favourite; a sweetheart.
- A male lover.