The most common and most likely answer to this crossword clue is the 9 letter word SUFFERING
I've seen this crossword clue in The Daily Telegraph
S
U
F
F
E
R
I
N
G
Buddy explains!

The straight part
We know that "ordeal" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ordeal = suffering.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 SUFFERING mean?
SUFFERING verb- To undergo hardship.
- To feel pain.
- To become worse.
- To endure, undergo.
- To allow.
- The condition of someone who suffers; a state of pain or distress.
- Experiencing pain.