The most common and most likely answer to this crossword clue is the 5 letter word GREBO
G
R
E
B
O
Buddy explains!

The straight part
We know that "Unkempt" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unkempt = grebo.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 GREBO mean?
GREBO noun- (predominantly West Midlands) A greaser or biker; a member of any alternative subculture, as opposed to a chav or townie.
- A member of a United Kingdom subculture of the late 1980s and early 1990s, musically affiliated with garage rock and electronica, typically wearing baggy clothes and hair in high ponytails.