The most common and most likely answer to this crossword clue is the 12 letter word BREATHALYSER
I've seen this crossword clue in The Guardian
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More clues leading to the result BREATHALYSER
- Best ale Harry’s drunk — reason why he won't risk driving?
- This may indicate a late sherry got drunk after opening of brandy!
- Its appearance may mean a blow for the motorist
- Test for driver of high-speed train, about to turn back after money cut
- Drunk say later associated with rehab after touch of alcoholism is outed — by this?
- Loudly departing, father's barely drunk? It may prove otherwise
Buddy explains!
The straight part
We know that "Its appearance may mean a blow for the motorist" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case its appearance may mean a blow for the motorist = breathalyser.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 BREATHALYSER mean?
BREATHALYSER noun- A device that measures alcohol in expired air so as to estimate the concentration of alcohol in a person's blood; used by traffic police in cases of suspected driving while under the influence of alcohol.