Sailed over with pacifist (4)
I believe the answer is:
dove
'pacifist' is the definition.
(dove is a kind of pacifist)
'sailed over with' is the wordplay.
'with' indicates a hidden word.
'DOVE' is hidden in the letters of 'sailed over'.
(Other definitions for dove that I've seen before include "plunged in the Grand Canyon" , "Peaceful type" , "Bird; advocate of peace" , "Bird[s]" , "Pigeon-like bird" .)