The most common and most likely answer to this crossword clue is the 7 letter word SUNROOM
S
U
N
R
O
O
M
Buddy explains!

The straight part
We know that "parlour, bright/l" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case parlour, bright/l = sunroom.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 SUNROOM mean?
SUNROOM noun- A room in a residence with numerous large windows admitting sunlight.
- Solarium