It takes aback? (5)
I believe the answer is:
rides
'takes aback?' is the definition.
The answer and definition can be both to do with fundamental existence as well as being verbs in their -s form.
Perhaps there's a link between them I don't understand?
'it' is the wordplay.
I cannot really understand how this works, but
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found within the answer.
The remaining letters 'rids' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for rides that I've seen before include "Dries out for vehicle journeys" , "Travels on an animal" , "Travels on horse or bicycle" , "Goes on a horse" , "Theme park attractions" .)