The most common and most likely answer to this crossword clue is the 9 letter word STOMACHED
I've seen this crossword clue in The Guardian
S
T
O
M
A
C
H
E
D
More clues leading to the result STOMACHED
Buddy explains!

The straight part
We know that "bore" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bore = stomached.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 STOMACHED mean?
STOMACHED verb- To tolerate (something), emotionally, physically, or mentally; to stand or handle something.
- To be angry.
- To resent; to remember with anger; to dislike.
- To turn the stomach of; to sicken or repel.