The most common and most likely answer to this crossword clue is the 11 letter word FURTHERMORE
I've seen this crossword clue in Financial Times
F
U
R
T
H
E
R
M
O
R
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.
What does FURTHERMORE mean?
FURTHERMORE adverb- In addition; besides; what's more; used to denote additional information.