It takes some people a very long time to get permission (5)
I believe the answer is:
leave
This could be a double definition.
'it takes some people a very long time' is the first definition.
The definition suggests a singular noun which matches the answer.
'permission' is the second definition.
(leave is permission or authorisation)
'to get' acts as a link.
Can you help me to learn more?
(Other definitions for leave that I've seen before include "Go away on holiday" , "Skip" , "Depart on work holiday?" , "Renounce" , "Permission - time off" .)