Front page story: priest punches hack (6)
I believe the answer is:
splash
'front page story' is the definition.
(term for an attention-grabbing front page)
'priest punches hack' is the wordplay.
'priest' becomes 'p' (ecclesiastical abbreviation).
'punches' means one lot of letters goes inside another (punch can mean to create a hole in).
'hack' becomes 'slash' (slash can mean to hack or chop).
'p' inserted inside 'slash' is 'SPLASH'.
(Other definitions for splash that I've seen before include "Effect of hitting water (or headlines!)" , "Display (a story) prominently in a newspaper" , "Watery sound" , "Fall in irregular drops" , "Prominent front page news story" .)