Japanese honorific (6)
'japanese honorific' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for san that I've seen before include "Hospital (abbrev.)" , "South African bushman; convalescent hospital" , "- - Francisco" , "sickbay" , "Health resort" .)
(Another definition for sensei that I've seen is " Teacher".)