The most common and most likely answer to this crossword clue is the 10 letter word DIABOLICAL
I've seen this crossword clue in The Daily Telegraph
D
I
A
B
O
L
I
C
A
L
More clues leading to the result DIABOLICAL
Buddy explains!
The straight part
We know that "What you might call hell" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case what you might call hell = diabolical.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 DIABOLICAL mean?
DIABOLICAL adjective- Extremely wicked or cruel.
- Of or concerning the devil; satanic.