Scoff about son's bearing (4)
I believe the answer is:
east
'bearing' is the definition.
(a compass bearing)
'scoff about son's' is the wordplay.
'scoff' becomes 'eat' (I've seen this before).
'about' means one lot of letters goes inside another.
'eat' placed around 's' is 'EAST'.
(Other definitions for east that I've seen before include "One regularly holding hands" , "course" , "Asia" , "Tom's friend" , "Airport near Derby" .)