But a greyhound can get out of it (4)
I believe the answer is:
trap
'out of it' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe there's an association between them I don't understand?
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for trap that I've seen before include "Snare; light carriage" , "Hook" , "Light horse-drawn carriage" , "Confine" , "Means of transport (sometime sprung!)" .)