The most common and most likely answer to this crossword clue is the 7 letter word LOUVRES
I've seen this crossword clue in Financial Times
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More clues leading to the result LOUVRES
Buddy explains!
The straight part
We know that "slatted doors or windows" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case slatted doors or windows = louvres.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 LOUVRES mean?
LOUVRES noun- A type of turret on the roof of certain medieval buildings designed to allow ventilation or the admission of light.
- (chiefly in plural) A series of sloping overlapping slats or boards which admit air and light but exclude rain etc.
- Any of a system of slits, as in the hood of an automobile, for ventilation.