Sailors had reportedly run off (7)
I believe the answer is:
abscond
'run off' is the definition.
(synonyms)
'sailors had reportedly' is the wordplay.
'sailors' becomes 'abs' (AB is short for able seaman).
'had reportedly' becomes 'cond' (I can't explain this - if you can you should give a lot more credence to this answer).
'abs'+'cond'='ABSCOND'
Can you help me to learn more?
(Other definitions for abscond that I've seen before include "Leave hurriedly to escape a legal process" , "make quick getaway" , "Fly" , "scarper" , "Do a bunk" .)