The most common and most likely answer to this crossword clue is the 8 letter word LOATHING
I've seen this crossword clue in The Daily Telegraph
L
O
A
T
H
I
N
G
More clues leading to the result LOATHING
- Detesting endless freight, object
- See an object bringing detestation
- Seen in diary, a slight feeling of revulsion
- See, a slight phobia could become abhorrence
- Ill feeling of Heather keeping promise
- See an article creating hatred
- Dislike a mobile with no light
- Rocky hit in advance by Ragin’ Bull, causing disgust
- Nick revolts displaying sheer hatred
- Heather describes expletive that causes hatred
Buddy explains!

The straight part
We know that "Ill feeling" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ill feeling = loathing.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 LOATHING mean?
LOATHING verb- To detest, hate, revile.
- Sense of revulsion, distaste, detestation, extreme hatred or dislike.