Cryptic crossword clue
Marx perhaps converted usher in German city 9

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

I've seen this crossword clue in Financial Times
K
A
R
L
S
R
U
H
E

Buddy explains!

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.

Latest crossword clues with full explanations