Declared open verdict suss (5)
I believe the answer is:
cried
'declared open verdict suss' is the definition.
The answer and definition can be both to do with communicating as well as being past participle verbs.
Maybe there's a link between them I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for cried that I've seen before include "Shed tears" , "Sobbed" , "Wept or called out" , "announced" , "Yelled" .)