The most common and most likely answer to this crossword clue is the 8 letter word STOCKADE
I've seen this crossword clue in The Times
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More clues leading to the result STOCKADE
- Farm animals forced to abandon leader, penned here?
- Farm animals, regularly handled in this enclosure
- In fort, help to pronounce on part of rifle
- Doc takes out pen
- Standard saddle regularly found in old fort
- Defence of cod, skate, flounder
- Barrier standard gets vocal support
- Defensive barrier, square, for rebel holding king
- Break code — task providing defence
- Stupidly dock at point under bottom of Thames Barrier
Buddy explains!

The straight part
We know that "penned here" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case penned here = stockade.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 STOCKADE mean?
STOCKADE noun- An enclosure protected by a wall of wooden posts
- A military prison
- To enclose in a stockade.