The most common and most likely answer to this crossword clue is the 8 letter word BECALMED
I've seen this crossword clue in Financial Times
B
E
C
A
L
M
E
D
Buddy explains!

The straight part
We know that "in the doldrums" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in the doldrums = becalmed.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 BECALMED mean?
BECALMED verb- To make calm or still; make quiet; calm.
- To deprive (a ship) of wind, so that it cannot move (usually in passive).
- (of a sailing ship) Unable to move due to lack of wind.