Never return without the right level (4)
I believe the answer is:
even
'level' is the definition.
(similar in meaning)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for even that I've seen before include "Not easily annoyed" , "Flat, level" , "Nearly" , "of consistent quality" , "Deep crisp snow seen on Boxing Day also this" .)