Press graduate probing company making a comeback (5)
I believe the answer is:
clamp
'press' is the definition.
(thesaurus)
'graduate probing company making a comeback' is the wordplay.
'graduate' becomes 'ma' (abbreviation for Master of Arts).
'probing' indicates putting letters inside (probe can mean to make a hole in).
'company' becomes 'plc' (abbreviation for public limited company).
'making a comeback' says the letters should be written backwards.
'ma' put into 'plc' is 'pmalc'.
'pmalc' in reverse letter order is 'CLAMP'.
(Other definitions for clamp that I've seen before include "pile of turf" , "Firmly hold" , "Make fast" , "stack of bricks" , "bracket" .)