The most common and most likely answer to this crossword clue is the 8 letter word FREAKISH
I've seen this crossword clue in Financial Times
F
R
E
A
K
I
S
H
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 FREAKISH mean?
FREAKISH adjective- Resembling a freak.
- Strange, unusual, abnormal or bizarre.
- Capricious, unpredictable.