Cryptic crossword clue
Most current peters out in river 9

The most common and most likely answer to this crossword clue is the 9 letter word TRENDIEST

I've seen this crossword clue in The Guardian
T
R
E
N
D
I
E
S
T


Buddy explains!

The straight part
We know that "Most current" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case most current = trendiest.
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 TRENDIEST mean?

TRENDIEST adjective
  1. Of, or in accordance with the latest trend, fashion or hype.

Latest crossword clues with full explanations