A Mass for those arrested and picked up by Brezhnev astonishingly (4)
I believe the answer is:
save
'a mass' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for save that I've seen before include "Apart from" , "Rescue or salt away" , "Rescue - except" , "Spend less" , "Bar" .)