The most common and most likely answer to this crossword clue is the 9 letter word OCTAGONAL
I've seen this crossword clue in Independent
O
C
T
A
G
O
N
A
L
More clues leading to the result OCTAGONAL
- Firm flips label on a line showing several faces
- A lot can go wrong with quite a few sides
- With eight sides in National League heading for administration, first month has past
- Month of death is of a certain shape
- A month previously, a line of certain dimensions.
- One month in the past ace cook stopped short of having many sides
- Kind of figure on coalgate, finally pointless to unravel
- Design a long coat shaped like an umbrella?
- Not a lot can go with appearance of stop sign
- As a stop sign can go a lot out of shape
Buddy explains!

The straight part
We know that "shaped like an umbrella?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case shaped like an umbrella? = octagonal.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 OCTAGONAL mean?
OCTAGONAL adjective- Shaped like an octagon, in having eight sides and eight angles.