The most common and most likely answer to this crossword clue is the 6 letter word ICEMEN
I've seen this crossword clue in Financial Times
I
C
E
M
E
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 ICEMEN mean?
ICEMEN noun- A person who trades in ice.
- A man who is skilled in travelling upon ice, as among glaciers.
- An assassin.
- One who is cool under pressure.
- A man in attendance at a frozen pond where skating etc. is going on.