Peripheral YouTubers are not busy (5)

I believe the answer is:

outer

I'm a little stuck... Click here to teach me more about this clue!

'peripheral' is the definition.
(I've seen this in another clue)

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for outer that I've seen before include "Poor shot" , "External; part of archery target" , "This space is beyond earth's atmosphere" , "Ring furthest from the bullseye" , "Surrounding" .)

I've seen this clue in the Sydney Morning Herald.

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