The most common and most likely answer to this crossword clue is the 5 letter word BOSUN
I've seen this crossword clue in Financial Times
B
O
S
U
N
More clues leading to the result BOSUN
- Seaman in sub? No, transferred
- Aggressive seabird turning like this with cake around?
- Hairstyle covers very retro crew member
- Box office star who controls crew?
- Sailor’s prize switched compass headings
- Naval officer warmer on the outskirts of Borneo
- Petty officer on sub at sea
- Officer at sea bawling out sailor upsets newcomers at start
Buddy explains!

The straight part
We know that "Sailor" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sailor = bosun.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 BOSUN mean?
BOSUN noun- A warrant or petty officer on board a naval ship.