The most common and most likely answer to this crossword clue is the 9 letter word EMBELLISH
I've seen this crossword clue in The Times
E
M
B
E
L
L
I
S
H
More clues leading to the result EMBELLISH
- European doctor, awfully bad, heading off to dress up
- Decorate English doctor — he's working with ill
- Deck me up rather like a Brontë sister?
- Large space beside ring is hard to improve
- Sorry about thousand libels, criminally elaborate
- Dress up retiring setter rather like Big Ben?
- Improve the appearance of space quite like a Clanger?
- Letter by former England batsman is hard to illustrate
- Decorate half of them rather like Big Ben?
- Initially Eastern market ring is hard to change for the better
Buddy explains!

The straight part
We know that "Decorate" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case decorate = embellish.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 EMBELLISH mean?
EMBELLISH verb- To make more beautiful and attractive; to decorate.
- To make something sound or look better or more acceptable than it is in reality; to distort, to embroider.