Complex way to end communication? (4-2)

I believe the answer is:

hang-up

I believe this is a double definition.

'complex' is the first definition.
(thesaurus)

'way to end communication?' is the second definition.
(as in hanging up the phone)

(Other definitions for hang-up that I've seen before include "Emotional problem or inhibition" , "Suspend" .)

I've seen this clue in The Guardian.

Want a hint initially instead of a full solution? Install my app