The most common and most likely answer to this crossword clue is the 8 letter word DULLARDS
I've seen this crossword clue in The Daily Telegraph
D
U
L
L
A
R
D
S
More clues leading to the result DULLARDS
Buddy explains!
The straight part
We know that "slow people" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case slow people = dullards.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 DULLARDS mean?
DULLARDS noun- A stupid person; a fool.