The most common and most likely answer to this crossword clue is the 10 letter word DECELERATE
I've seen this crossword clue in The Guardian
D
E
C
E
L
E
R
A
T
E
More clues leading to the result DECELERATE
- Slow month on railroad, with terminally tiresome speed
- Ant’s friend, celeb: ‘Unlimited speed? Slow down!’
- Champagne’ s from VIP, having reduced price to ease up
- Slow down in river when treacle’s poured in
- Slow down, drive avoiding the median. Maintain speed following safety mark seen on lane ends
- Slow down in river when treacle stirred in?
- Late decree — ordered to slow down
- Slow divorce case? Then have a party from which husband heartily excluded
Buddy explains!
The straight part
We know that "slow down" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case slow down = decelerate.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 DECELERATE mean?
DECELERATE verb- To reduce the velocity of something
- To reduce the rate of advancement of something, such as a disease
- To go slower