The most common and most likely answer to this crossword clue is the 8 letter word REACTING
I've seen this crossword clue in The Daily Telegraph
R
E
A
C
T
I
N
G
More clues leading to the result REACTING
Buddy explains!
The straight part
We know that "showing uncooperative attitude" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case showing uncooperative attitude = reacting.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 REACTING mean?
REACTING verb- To act or perform a second time; to do over again; to reenact.
- To return an impulse or impression; to resist the action of another body by an opposite force
- To act upon each other; to exercise a reciprocal or a reverse effect, as two or more chemical agents; to act in opposition.
- To cause chemical agents to react; to cause one chemical agent to react with another.