The most common and most likely answer to this crossword clue is the 4 plus 4 letter word WEAR THIN
I've seen this crossword clue in The Times
W
E
A
R
T
H
I
N
More clues leading to the result WEAR THIN
- Success securing wire to become less convincing
- Gradually become less persuasive dancing in the raw
- Mobilising in the war, start to be ineffective
- Succeed across the world and become tedious
- Patience when abused may succeed in circling the world
- Get less convincing victory protecting the planet
- Become less believable with victory involving something dirty
- Beat one’s opponents crossing ground, but become less convincing
- Victory in which heart is broken to become less convincing
- Victory spanning the world to become less plausible?
Buddy explains!
The straight part
We know that "Gradually become less persuasive" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gradually become less persuasive = wear thin.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.