The most common and most likely answer to this crossword clue is the 4 letter word FUZZ
I've seen this crossword clue in The Guardian
F
U
Z
Z
More clues leading to the result FUZZ
Buddy explains!
The straight part
We know that "The Boys in Blue/Blur" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case the boys in blue/blur = fuzz.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 FUZZ mean?
FUZZ noun- A frizzy mass of hair or fibre.
- Quality of an image that is unclear; a blurred image.
- The random data used in fuzz testing.
- A distorted sound, especially from an electric guitar or other amplified instrument.
- A state of befuddlement.
- To make fuzzy.
- To become fuzzy.
- To make drunk.
- To test a software component by running it on randomly generated input.
- To fly off in minute particles with a fizzing sound, like water from hot metal.
- (with "the") The police.