The most common and most likely answer to this crossword clue is the 4 plus 6 letter word OPEN SEASON
I've seen this crossword clue in Independent
O
P
E
N
S
E
A
S
O
N
More clues leading to the result OPEN SEASON
- Starts with each child's unrestricted period for game
- Main issue when hunting is permitted
- A time to criticise when golf tournaments are played?
- Old writer reportedly to snatch feasible time when anything goes
- International waters in effect from 12 August
- Free time when attacks are to be expected
- Pheasant and so on we butchered? Could be this, what?
- Female swan protected by one, as so flustered when hunting is allowed
- A time to hunt in clear oceans – proceed!
- Start to add flavour to food at this time of year
Buddy explains!

The straight part
We know that "when hunting is permitted" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case when hunting is permitted = open season.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.