Exert force on a chap to be a journalist (8)
I believe the answer is:
pressman
'a journalist' is the definition.
(I know that pressman is a type of journalist)
'exert force on a chap' is the wordplay.
'exert force on' becomes 'press' (I've seen this before).
'a chap' becomes 'man' (chap can mean a man).
'press'+'man'='PRESSMAN'
'to be' is the link.
(Other definitions for pressman that I've seen before include "correspondent?" , "Male journalist" .)