Shock as tabloid pinches Telegraph leader (4)
I believe the answer is:
stun
'shock' is the definition.
(synonyms)
'tabloid pinches telegraph leader' is the wordplay.
'tabloid' becomes 'sun' (The Sun, UK newspaper).
'pinches' indicates putting letters inside (pinch can mean to steal).
'leader' indicates taking the first letters.
The first letter of 'telegraph' is 't'.
'sun' enclosing 't' is 'STUN'.
'as' acts as a link.
(Other definitions for stun that I've seen before include "Make senseless or dizzy with a blow" , "Make dazed or numb" , "Stagger, amaze" , "Anaesthetise" , "Daze, knock senseless" .)