The most common and most likely answer to this crossword clue is the 5 letter word FAULT
I've seen this crossword clue in The Guardian
F
A
U
L
T
More clues leading to the result FAULT
Buddy explains!
The straight part
We know that "Criticise/bad service" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case criticise/bad service = fault.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 FAULT mean?
FAULT noun- A defect; something that detracts from perfection.
- A mistake or error.
- A weakness of character; a failing.
- A minor offense.
- Blame; the responsibility for a mistake.
- A fracture in a rock formation causing a discontinuity.
- In coal seams, coal rendered worthless by impurities in the seam.
- An illegal serve.
- An abnormal connection in a circuit.
- Want; lack
- A lost scent; act of losing the scent.
- To criticize, blame or find fault with something or someone.
- To fracture.
- To commit a mistake or error.
- To undergo a page fault.