The most common and most likely answer to this crossword clue is the 9 letter word OUTSPREAD
I've seen this crossword clue in The Daily Telegraph
O
U
T
S
P
R
E
A
D
More clues leading to the result OUTSPREAD
- Reveals quiet study, fully extended
- Reveals quiet study that's fully extended
- Unfolded drapes, cryptically
- Openly gay array of food unfolded?
- Extended, as a picnic meal, say?
- Fully extended providing picnic?
- Extend lavish picnic?
- Put so badly, study gets extended
- Extended alfresco meal
- Wide-open rolling pasture surrounded by woods regularly overlooked
Buddy explains!

The straight part
We know that "Extended" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case extended = outspread.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 OUTSPREAD mean?
OUTSPREAD verb- To spread out; expand; extend.
- Extended outward, as one's arms