The most common and most likely answer to this crossword clue is the 3 plus 4 letter word ILL WILL
I've seen this crossword clue in The Guardian
I
L
L
W
I
L
L
More clues leading to the result ILL WILL
- Dislike current lines by bard
- Perhaps Shakespeare under the weather provides Iago’s motivation?
- Around wife, Everyman shall repeatedly feud
- Repeatedly sick over women, creating resentment
- Bitterness of individual lines by the Bard
- Bad blood in Israel, involving central character of Old Testament
- Sick twice, absorbing wife’s hostility
- Aversion one shows with lines written by Shakespeare?
- All entering into conjugal promise without a bad feeling
- Sick testament radiates malice
Buddy explains!

The straight part
We know that "Bad blood" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bad blood = ill will.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.