The most common and most likely answer to this crossword clue is the 8 letter word CLASHING
I've seen this crossword clue in The Daily Telegraph
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Buddy explains!

The straight part
We know that "In conflict" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in conflict = clashing.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 CLASHING mean?
CLASHING verb- To make a clashing sound.
- To cause to make a clashing sound.
- To come into violent conflict.
- To argue angrily.
- (in games or sports) To face each other in an important game.
- (of clothes, decor, colours) To fail to look good together; to contrast unattractively; to fail to harmonize.
- (of events) To coincide, to happen at the same time, thereby rendering it impossible to attend all.
- To chatter or gossip.
- A clash; the sound or action of clashing; violent collision.
- Conflicting, contrasting, or contrary; inconsonant, incompatible, or irreconcilable
- Mismatched, inharmonious, discordant or dissonant, not fitting well together (especially in regards to aesthetics, colors, clothing, or sounds)
- Adverse or antagonistic; disagreeing or opposing