The most common and most likely answer to this crossword clue is the 9 letter word PROTECTOR
I've seen this crossword clue in The Daily Telegraph
P
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More clues leading to the result PROTECTOR
Buddy explains!
The straight part
We know that "guard" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case guard = protector.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 PROTECTOR mean?
PROTECTOR noun- Someone who protects or guards, by assignment or on their own initiative.
- A device or mechanism which is designed to protect.
- One who prevents interference.
- A state or other subject under international law, exercising a protectorate over another subject in international law.
- One having the care of the kingdom during the king's minority; a regent.
- A cardinal, from one of the more considerable Roman Catholic nations, who looks after the interests of his people at Rome; also, a cardinal who has the same relation to a college, religious order, etc.