Insisted reporters join journalist (7)
I believe the answer is:
pressed
'insisted' is the definition.
The answer and definition can be both to do with communicating as well as being past participle verbs.
Perhaps you can see an association between them that I don't see?
'reporters join journalist' is the wordplay.
'reporters' becomes 'press' (newspaper reporters).
'join' means one lot of letters go next to another.
'journalist' becomes 'ed' (short for editor).
'press'+'ed'='PRESSED'
Can you help me to learn more?
(Other definitions for pressed that I've seen before include "Argued strongly and exerted force" , "under some strain" , "Squeezed hard" , "crushed juice" , "Urged U crushed" .)