Arrest sailor following end of altercation (3)
I believe the answer is:
nab
'arrest' is the definition.
(synonyms)
'sailor following end of altercation' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'following' says to put letters next to each other.
'end of' says to take the final letters.
The final letter of 'altercation' is 'n'.
'ab' put after 'n' is 'NAB'.
(Other definitions for nab that I've seen before include "Catch (thief) (colloq.)" , "Capture, catch" , "Arrest (colloq.)" , "Seize quickly" , "Catch; grab suddenly" .)