Signaller crushed grape (5)
I believe the answer is:
pager
'signaller' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'crushed grape' is the wordplay.
'crushed' indicates anagramming the letters.
'grape' anagrammed gives 'PAGER'.
Can you help me to learn more?
(Other definitions for pager that I've seen before include "Contact device" , "Radio alert device" , "message on this?" , "Old electronic bleeping device" , "This may summon one" .)