The most common and most likely answer to this crossword clue is the 10 letter word EXASPERATE
I've seen this crossword clue in The Times
E
X
A
S
P
E
R
A
T
E
More clues leading to the result EXASPERATE
- Fell over gorge, netting a bug
- . Madden and mischievously pester a former associate at the start
- Anger old queen – snake, being clasped, bit
- Get frustrated as former partner repeats a failing
- Enrage former Queen, bit embracing snake
- State has to work without leaders — that’s enough to make you mad
- Axe swung before trashy repeats cause acute irritation
- Anger of former Queen, bit clutching snake
Buddy explains!

The straight part
We know that "bug" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bug = exasperate.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 EXASPERATE mean?
EXASPERATE verb- To tax the patience of, irk, frustrate, vex, provoke, annoy; to make angry.
- Exasperated; embittered.