The most common and most likely answer to this crossword clue is the 7 letter word RAMPART
I've seen this crossword clue in The Times
R
A
M
P
A
R
T
More clues leading to the result RAMPART
- Pack forcibly split defence
- Sheep bit castle defenders here?
- Defensive structure in the Suffolk area?
- Defence requiring inclination and skill
- Horn for defence?
- Academy paintings captivate minister for defence
- Animal found next to section of embankment
- Drive home and go off Embankment
- An animal must have some means of defence
- Take damage going over barricade
Buddy explains!

The straight part
We know that "defence" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case defence = rampart.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 RAMPART mean?
RAMPART noun- A defensive mound of earth or a wall with a broad top and usually a stone parapet; a wall-like ridge of earth, stones or debris; an embankment for defensive purpose.
- A defensive structure; a protective barrier; a bulwark.
- That which defends against intrusion from outside; a protection.
- (usually in the plural) A steep bank of a river or gorge.
- To defend with a rampart; fortify or surround with a rampart.