Time in a resort causes concern (9)
I believe the answer is:
operation
'concern' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'time in a resort' is the wordplay.
'time' becomes 'era' (an era is a period of time).
'in' is an insertion indicator.
'a resort' becomes 'option' (I am not sure about this - if you are sure you should believe this answer much more).
'era' placed within 'option' is 'OPERATION'.
'causes' acts as a link.
Can you help me to learn more?
(Other definitions for operation that I've seen before include "Theatre procedure" , "working" , "Action; process" , "military undertaking" , "running" .)