The most common and most likely answer to this crossword clue is the 7 letter word TYCOONS
I've seen this crossword clue in The Daily Telegraph
T
Y
C
O
O
N
S
Buddy explains!
The straight part
We know that "businessmen of great power" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case businessmen of great power = tycoons.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 TYCOONS mean?
TYCOONS noun- A wealthy and powerful business person.