Eating here is no picnic (7)
I believe the answer is:
'eating here' is the definition.
Both the answer and definition are adverbs. Maybe you can see an association between them that I can't see?
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for indoors that I've seen before include "Within house" , "Within the four walls" , "Within a building" , "under cover" , "safe from the weather" .)