The most common and most likely answer to this crossword clue is the 8 letter word DEVILISH
I've seen this crossword clue in The Daily Telegraph
D
E
V
I
L
I
S
H
More clues leading to the result DEVILISH
- Cunning good-looker, wicked inside
- Extreme inhumanity in beauty
- Attractive person concealing wickedness is diabolical
- Satanic underworld god welcomes wicked husband
- Unspeakable wickedness in beauty
- Diabolical meal causing misfortune inside
- He’s livid, agitated yet mischievous
- Very sinful, like a spicy meal?
- Good-looking woman — inside is wicked, very wicked
- Extremely wrong to be consumed by stunner? Indeed
Buddy explains!

The straight part
We know that "Indeed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case indeed = devilish.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 DEVILISH mean?
DEVILISH adjective- Resembling a devil.
- Characteristic of a devil.
- Extreme, excessive.
- Devilishly; very; exceedingly.