The most common and most likely answer to this crossword clue is the 8 letter word COMEDOWN
I've seen this crossword clue in Financial Times
C
O
M
E
D
O
W
N
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 COMEDOWN mean?
COMEDOWN noun- A sudden drop to a lower status, condition or level; a disappointment or letdown
- A calm, mellow period experienced after the initial high from taking drugs