The most common and most likely answer to this crossword clue is the 4 plus 3 letter word JACK TAR
I've seen this crossword clue in The Times
J
A
C
K
T
A
R
More clues leading to the result JACK TAR
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 = jack tar.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.
Crossword Answer definitions
JACK TAR noun- Nickname for a sailor in the Royal Navy.