And the sailor goes first to get on leave (7)
I believe the answer is:
abandon
'leave' is the definition.
(to abandon is to leave or desert)
'and the sailor goes first to get on' is the wordplay.
'the sailor' becomes 'ab' (abbreviation for able seaman).
'goes first' says to put letters next to each other.
'to get' is a charade indicator (letters next to each other).
'and' after 'ab' is 'aband'.
'aband'+'on'='ABANDON'
(Other definitions for abandon that I've seen before include "dump" , "Kick" , "Leave in the lurch" , "Czech city" , "Jack in" .)