The most common and most likely answer to this crossword clue is the 5 letter word NOOKS
I've seen this crossword clue in The Guardian
N
O
O
K
S
More clues leading to the result NOOKS
- Retreats, when there’s nothing but rejection?
- New unopened volumes found in hiding places
- Retreats in numbers, receiving permission
- Complete absence of sanctions in retreats
- Retreats agreed in numbers
- Sanction stops child turning corners
- Refusal to allow some short corners
- Cramped spaces are fine in small numbers
- Refusal to sanction small corners
- Retreats as negative vote’s accepting sanction
Buddy explains!

The straight part
We know that "Retreats" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case retreats = nooks.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 NOOKS mean?
NOOKS noun- A small corner formed by two walls; an alcove.
- A hidden or secluded spot; a secluded retreat.
- A recess, cove or hollow.
- An English unit of land area, originally 1/4 of a yardland but later 12 1/2 or 20 acres.
- A corner of a piece of land; an angled piece of land, especially one extending into other land.
- To withdraw into a nook.
- To situate in a nook.