The most common and most likely answer to this crossword clue is the 6 letter word ABLOOM
I've seen this crossword clue in The Times
A
B
L
O
O
M
More clues leading to the result ABLOOM
- Bachelor imprisoned in a tower gets out
- A report catching Labour’s leader out
- Sailor leading ladies and maiden out
- A Pole that criminal finally breaks out
- Part of six-pack: Mark carrying can out
- Jack, John and Miles covered in flowers
- Sailor to threaten bursting out
- Billions in cash for backing out
- Efflorescent answer by Orlando, perhaps
- Head of bakery poked in bread before turning out
Buddy explains!

The straight part
We know that "out" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case out = abloom.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 ABLOOM mean?
ABLOOM adjective- Blooming; covered in flowers.
- Having something growing or grown.
- Thriving in health, beauty, and vigor; exhibiting youth-like beauty.
- In or into bloom; in a blooming state; having flower blooms unfolding.