Complex way to end a call (4-2)

I believe the answer is:

hang-up

I believe this clue is a double definition.

'complex' is the first definition.
(thesaurus)

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

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

I've seen this clue in The Times.

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