The most common and most likely answer to this crossword clue is the 8 letter word KNEEPADS
I've seen this crossword clue in The Guardian
K
N
E
E
P
A
D
S
Buddy explains!
The straight part
We know that "Guards/Guards" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case guards/guards = kneepads.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 KNEEPADS mean?
KNEEPADS noun- A protective garment worn on a knee to protect it from injury, for example due to a blow or a fall.