Worry that may be going (7)
I believe the answer is:
concern
'worry' is the definition.
(I know that worry can be written as concern)
'going' is the wordplay.
I cannot quite understand how this works, but
'going' could be 'on' (both can mean functioning or activated) and 'on' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'that may be' is the link.
Can you help me to learn more?
(Other definitions for concern that I've seen before include "Business - worry" , "Cause of anxiety" , "Firm - interest" , "Feeling of anxiety or sympathy" , "Have something to do with" .)