The most common and most likely answer to this crossword clue is the 7 letter word PORTEND
I've seen this crossword clue in Financial Times
P
O
R
T
E
N
D
More clues leading to the result PORTEND
- Left at sea, aim to make forecast
- Left back to warn of trouble
- Drink leading to death of herald
- Betoken something far from right at sea?
- Threaten to be left to finish
- Finish wine before making forecast
- Left back, mean
- Herald left, getting wind up
- Point to what might indicate the open sea?
- Signal left with purpose
Buddy explains!

The straight part
We know that "Betoken" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case betoken = portend.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 PORTEND mean?
PORTEND verb- To serve as a warning or omen of.
- To signify; to denote.